diff --git a/build.gradle b/build.gradle
--- a/build.gradle
+++ b/build.gradle
@@ -8,6 +8,7 @@ typescript {
         lib = ["es5", "dom", "scripthost", "es2015.promise", "es2015.symbol", "es2015.iterable"]
         listFiles = true
         declaration = true
+        strict = true
         types = []
         module = "amd"
         it.target = "es5"
diff --git a/package-lock.json b/package-lock.json
--- a/package-lock.json
+++ b/package-lock.json
@@ -22,6 +22,15 @@
                 "js-tokens": "^4.0.0"
             }
         },
+        "@babel/runtime": {
+            "version": "7.8.3",
+            "resolved": "https://registry.npmjs.org/@babel/runtime/-/runtime-7.8.3.tgz",
+            "integrity": "sha512-fVHx1rzEmwB130VTkLnxR+HmxcTjGzH12LYQcFFoBwakMd3aOMD4OsRN7tGG/UOYE2ektgFrS8uACAoRk1CY0w==",
+            "dev": true,
+            "requires": {
+                "regenerator-runtime": "^0.13.2"
+            }
+        },
         "@implab/core-amd": {
             "version": "1.3.2",
             "resolved": "https://registry.npmjs.org/@implab/core-amd/-/core-amd-1.3.2.tgz",
@@ -29,15 +38,9 @@
             "dev": true
         },
         "@types/chai": {
-            "version": "4.2.7",
-            "resolved": "https://registry.npmjs.org/@types/chai/-/chai-4.2.7.tgz",
-            "integrity": "sha512-luq8meHGYwvky0O7u0eQZdA7B4Wd9owUCqvbw2m3XCrCU8mplYOujMBbvyS547AxJkC+pGnd0Cm15eNxEUNU8g==",
-            "dev": true
-        },
-        "@types/node": {
-            "version": "8.0.0",
-            "resolved": "https://registry.npmjs.org/@types/node/-/node-8.0.0.tgz",
-            "integrity": "sha512-j2tekvJCO7j22cs+LO6i0kRPhmQ9MXaPZ55TzOc1lzkN5b6BWqq4AFjl04s1oRRQ1v5rSe+KEvnLUSTonuls/A==",
+            "version": "4.1.3",
+            "resolved": "https://registry.npmjs.org/@types/chai/-/chai-4.1.3.tgz",
+            "integrity": "sha512-f5dXGzOJycyzSMdaXVhiBhauL4dYydXwVpavfQ1mVCaGjR56a9QfklXObUxlIY9bGTmCPHEEZ04I16BZ/8w5ww==",
             "dev": true
         },
         "@types/requirejs": {
@@ -46,14 +49,11 @@
             "integrity": "sha512-b2soeyuU76rMbcRJ4e0hEl0tbMhFwZeTC0VZnfuWlfGlk6BwWNsev6kFu/twKABPX29wkX84wU2o+cEJoXsiTw==",
             "dev": true
         },
-        "@types/tape": {
-            "version": "4.2.33",
-            "resolved": "https://registry.npmjs.org/@types/tape/-/tape-4.2.33.tgz",
-            "integrity": "sha512-ltfyuY5BIkYlGuQfwqzTDT8f0q8Z5DGppvUnWGs39oqDmMd6/UWhNpX3ZMh/VYvfxs3rFGHMrLC/eGRdLiDGuw==",
-            "dev": true,
-            "requires": {
-                "@types/node": "*"
-            }
+        "@types/yaml": {
+            "version": "1.2.0",
+            "resolved": "https://registry.npmjs.org/@types/yaml/-/yaml-1.2.0.tgz",
+            "integrity": "sha512-GW8b9qM+ebgW3/zjzPm0I1NxMvLaz/YKT9Ph6tTb+Fkeyzd9yLTvQ6ciQ2MorTRmb/qXmfjMerRpG4LviixaqQ==",
+            "dev": true
         },
         "acorn": {
             "version": "7.1.0",
@@ -80,15 +80,18 @@
             }
         },
         "ansi-escapes": {
-            "version": "3.2.0",
-            "resolved": "https://registry.npmjs.org/ansi-escapes/-/ansi-escapes-3.2.0.tgz",
-            "integrity": "sha512-cBhpre4ma+U0T1oM5fXg7Dy1Jw7zzwv7lt/GoCpr+hDQJoYnKVPLL4dCvSEFMmQurOQvSrwT7SL/DAlhBI97RQ==",
-            "dev": true
+            "version": "4.3.0",
+            "resolved": "https://registry.npmjs.org/ansi-escapes/-/ansi-escapes-4.3.0.tgz",
+            "integrity": "sha512-EiYhwo0v255HUL6eDyuLrXEkTi7WwVCLAw+SeOQ7M7qdun1z1pum4DEm/nuqIVbPvi9RPPc9k9LbyBv6H0DwVg==",
+            "dev": true,
+            "requires": {
+                "type-fest": "^0.8.1"
+            }
         },
         "ansi-regex": {
-            "version": "3.0.0",
-            "resolved": "https://registry.npmjs.org/ansi-regex/-/ansi-regex-3.0.0.tgz",
-            "integrity": "sha1-7QMXwyIGT3lGbAKWa922Bas32Zg=",
+            "version": "5.0.0",
+            "resolved": "https://registry.npmjs.org/ansi-regex/-/ansi-regex-5.0.0.tgz",
+            "integrity": "sha512-bY6fj56OUQ0hU1KjFNDQuJFezqKdrAyFdIevADiqrWHwSlbmBNMHp5ak2f40Pm8JTFyM2mqxkG6ngkHO11f/lg==",
             "dev": true
         },
         "ansi-styles": {
@@ -109,6 +112,12 @@
                 "sprintf-js": "~1.0.2"
             }
         },
+        "assertion-error": {
+            "version": "1.1.0",
+            "resolved": "https://registry.npmjs.org/assertion-error/-/assertion-error-1.1.0.tgz",
+            "integrity": "sha512-jgsaNduz+ndvGyFt3uSuWqvy4lCnIJiovtouQN5JZHOKCS2QuhEdbcQHFhVksz2N2U9hXJo8odG7ETyWlEeuDw==",
+            "dev": true
+        },
         "astral-regex": {
             "version": "1.0.0",
             "resolved": "https://registry.npmjs.org/astral-regex/-/astral-regex-1.0.0.tgz",
@@ -143,6 +152,20 @@
             "integrity": "sha512-P8BjAsXvZS+VIDUI11hHCQEv74YT67YUi5JJFNWIqL235sBmjX4+qx9Muvls5ivyNENctx46xQLQ3aTuE7ssaQ==",
             "dev": true
         },
+        "chai": {
+            "version": "4.2.0",
+            "resolved": "https://registry.npmjs.org/chai/-/chai-4.2.0.tgz",
+            "integrity": "sha512-XQU3bhBukrOsQCuwZndwGcCVQHyZi53fQ6Ys1Fym7E4olpIqqZZhhoFJoaKVvV17lWQoXYwgWN2nF5crA8J2jw==",
+            "dev": true,
+            "requires": {
+                "assertion-error": "^1.1.0",
+                "check-error": "^1.0.2",
+                "deep-eql": "^3.0.1",
+                "get-func-name": "^2.0.0",
+                "pathval": "^1.1.0",
+                "type-detect": "^4.0.5"
+            }
+        },
         "chalk": {
             "version": "2.4.2",
             "resolved": "https://registry.npmjs.org/chalk/-/chalk-2.4.2.tgz",
@@ -160,13 +183,19 @@
             "integrity": "sha512-mT8iDcrh03qDGRRmoA2hmBJnxpllMR+0/0qlzjqZES6NdiWDcZkCNAk4rPFZ9Q85r27unkiNNg8ZOiwZXBHwcA==",
             "dev": true
         },
+        "check-error": {
+            "version": "1.0.2",
+            "resolved": "https://registry.npmjs.org/check-error/-/check-error-1.0.2.tgz",
+            "integrity": "sha1-V00xLt2Iu13YkS6Sht1sCu1KrII=",
+            "dev": true
+        },
         "cli-cursor": {
-            "version": "2.1.0",
-            "resolved": "https://registry.npmjs.org/cli-cursor/-/cli-cursor-2.1.0.tgz",
-            "integrity": "sha1-s12sN2R5+sw+lHR9QdDQ9SOP/LU=",
+            "version": "3.1.0",
+            "resolved": "https://registry.npmjs.org/cli-cursor/-/cli-cursor-3.1.0.tgz",
+            "integrity": "sha512-I/zHAwsKf9FqGoXM4WWRACob9+SNukZTd94DWF57E4toouRulbCxcUh6RKUEOQlYTHJnzkPMySvPNaaSLNfLZw==",
             "dev": true,
             "requires": {
-                "restore-cursor": "^2.0.0"
+                "restore-cursor": "^3.1.0"
             }
         },
         "cli-width": {
@@ -232,11 +261,14 @@
                 "ms": "^2.1.1"
             }
         },
-        "deep-equal": {
-            "version": "1.0.1",
-            "resolved": "https://registry.npmjs.org/deep-equal/-/deep-equal-1.0.1.tgz",
-            "integrity": "sha1-9dJgKStmDghO/0zbyfCK0yR0SLU=",
-            "dev": true
+        "deep-eql": {
+            "version": "3.0.1",
+            "resolved": "https://registry.npmjs.org/deep-eql/-/deep-eql-3.0.1.tgz",
+            "integrity": "sha512-+QeIQyN5ZuO+3Uk5DYh6/1eKO0m0YmJFGNmFHGACpf1ClL1nmlV/p4gNgbl2pJGxgXb4faqo6UE+M5ACEMyVcw==",
+            "dev": true,
+            "requires": {
+                "type-detect": "^4.0.0"
+            }
         },
         "deep-is": {
             "version": "0.1.3",
@@ -244,25 +276,10 @@
             "integrity": "sha1-s2nW+128E+7PUk+RsHD+7cNXzzQ=",
             "dev": true
         },
-        "define-properties": {
-            "version": "1.1.3",
-            "resolved": "https://registry.npmjs.org/define-properties/-/define-properties-1.1.3.tgz",
-            "integrity": "sha512-3MqfYKj2lLzdMSf8ZIZE/V+Zuy+BgD6f164e8K2w7dgnpKArBDerGYpM46IYYcjnkdPNMjPk9A6VFB8+3SKlXQ==",
-            "dev": true,
-            "requires": {
-                "object-keys": "^1.0.12"
-            }
-        },
-        "defined": {
-            "version": "1.0.0",
-            "resolved": "https://registry.npmjs.org/defined/-/defined-1.0.0.tgz",
-            "integrity": "sha1-yY2bzvdWdBiOEQlpFRGZ45sfppM=",
-            "dev": true
-        },
         "diff": {
-            "version": "3.5.0",
-            "resolved": "https://registry.npmjs.org/diff/-/diff-3.5.0.tgz",
-            "integrity": "sha512-A46qtFgd+g7pDZinpnwiRJtxbC1hpgf0uzP3iG89scHk0AUC7A1TGxf5OiiOUv/JMZR8GOt8hL900hV0bOy5xA==",
+            "version": "4.0.2",
+            "resolved": "https://registry.npmjs.org/diff/-/diff-4.0.2.tgz",
+            "integrity": "sha512-58lmxKSA4BNyLz+HHMUzlOEpg09FV+ev6ZMe3vJihgdxzgcwZ8VoEEPmALCZG9LmqfVoNMMKpttIYTVG6uDY7A==",
             "dev": true
         },
         "doctrine": {
@@ -275,9 +292,9 @@
             }
         },
         "dojo": {
-            "version": "1.10.10",
-            "resolved": "https://registry.npmjs.org/dojo/-/dojo-1.10.10.tgz",
-            "integrity": "sha512-kg79C8Yyd317cG3MgXGMH4AeQ8TgNr8H/PpA3BRms7DTfl0CJCRAgGE/C6d9Nw55s1ID/fEsfS+P3bj1s7dWgA==",
+            "version": "1.16.0",
+            "resolved": "https://registry.npmjs.org/dojo/-/dojo-1.16.0.tgz",
+            "integrity": "sha512-DUiXyoLK6vMF5BPr/qiMLTxDMfiM9qlzN1jxfDsVfuvB/CwhYpNxA/M4mbqKN8PCVGLmccXBJbfmFJPP5+zmzw==",
             "dev": true
         },
         "dojo-typings": {
@@ -290,49 +307,11 @@
             }
         },
         "emoji-regex": {
-            "version": "7.0.3",
-            "resolved": "https://registry.npmjs.org/emoji-regex/-/emoji-regex-7.0.3.tgz",
-            "integrity": "sha512-CwBLREIQ7LvYFB0WyRvwhq5N5qPhc6PMjD6bYggFlI5YyDgl+0vxq5VHbMOFqLg7hfWzmu8T5Z1QofhmTIhItA==",
+            "version": "8.0.0",
+            "resolved": "https://registry.npmjs.org/emoji-regex/-/emoji-regex-8.0.0.tgz",
+            "integrity": "sha512-MSjYzcWNOA0ewAHpz0MxpYFvwg6yjy1NG3xteoqz644VCo/RPgnr1/GGt+ic3iJTzQ8Eu3TdM14SawnVUmGE6A==",
             "dev": true
         },
-        "es-abstract": {
-            "version": "1.17.4",
-            "resolved": "https://registry.npmjs.org/es-abstract/-/es-abstract-1.17.4.tgz",
-            "integrity": "sha512-Ae3um/gb8F0mui/jPL+QiqmglkUsaQf7FwBEHYIFkztkneosu9imhqHpBzQ3h1vit8t5iQ74t6PEVvphBZiuiQ==",
-            "dev": true,
-            "requires": {
-                "es-to-primitive": "^1.2.1",
-                "function-bind": "^1.1.1",
-                "has": "^1.0.3",
-                "has-symbols": "^1.0.1",
-                "is-callable": "^1.1.5",
-                "is-regex": "^1.0.5",
-                "object-inspect": "^1.7.0",
-                "object-keys": "^1.1.1",
-                "object.assign": "^4.1.0",
-                "string.prototype.trimleft": "^2.1.1",
-                "string.prototype.trimright": "^2.1.1"
-            },
-            "dependencies": {
-                "object-inspect": {
-                    "version": "1.7.0",
-                    "resolved": "https://registry.npmjs.org/object-inspect/-/object-inspect-1.7.0.tgz",
-                    "integrity": "sha512-a7pEHdh1xKIAgTySUGgLMx/xwDZskN1Ud6egYYN3EdRW4ZMPNEDUTF+hwy2LUC+Bl+SyLXANnwz/jyh/qutKUw==",
-                    "dev": true
-                }
-            }
-        },
-        "es-to-primitive": {
-            "version": "1.2.1",
-            "resolved": "https://registry.npmjs.org/es-to-primitive/-/es-to-primitive-1.2.1.tgz",
-            "integrity": "sha512-QCOllgZJtaUo9miYBcLChTUaHNjJF3PYs1VidD7AwiEj1kYxKeQTctLAezAOH5ZKRH0g2IgPn6KwB4IT8iRpvA==",
-            "dev": true,
-            "requires": {
-                "is-callable": "^1.1.4",
-                "is-date-object": "^1.0.1",
-                "is-symbol": "^1.0.2"
-            }
-        },
         "escape-string-regexp": {
             "version": "1.0.5",
             "resolved": "https://registry.npmjs.org/escape-string-regexp/-/escape-string-regexp-1.0.5.tgz",
@@ -340,9 +319,9 @@
             "dev": true
         },
         "eslint": {
-            "version": "6.1.0",
-            "resolved": "https://registry.npmjs.org/eslint/-/eslint-6.1.0.tgz",
-            "integrity": "sha512-QhrbdRD7ofuV09IuE2ySWBz0FyXCq0rriLTZXZqaWSI79CVtHVRdkFuFTViiqzZhkCgfOh9USpriuGN2gIpZDQ==",
+            "version": "6.8.0",
+            "resolved": "https://registry.npmjs.org/eslint/-/eslint-6.8.0.tgz",
+            "integrity": "sha512-K+Iayyo2LtyYhDSYwz5D5QdWw0hCacNzyq1Y821Xna2xSJj7cijoLLYmLxTQgcgZ9mC61nryMy9S7GRbYpI5Ig==",
             "dev": true,
             "requires": {
                 "@babel/code-frame": "^7.0.0",
@@ -352,19 +331,19 @@
                 "debug": "^4.0.1",
                 "doctrine": "^3.0.0",
                 "eslint-scope": "^5.0.0",
-                "eslint-utils": "^1.3.1",
-                "eslint-visitor-keys": "^1.0.0",
-                "espree": "^6.0.0",
+                "eslint-utils": "^1.4.3",
+                "eslint-visitor-keys": "^1.1.0",
+                "espree": "^6.1.2",
                 "esquery": "^1.0.1",
                 "esutils": "^2.0.2",
                 "file-entry-cache": "^5.0.1",
                 "functional-red-black-tree": "^1.0.1",
                 "glob-parent": "^5.0.0",
-                "globals": "^11.7.0",
+                "globals": "^12.1.0",
                 "ignore": "^4.0.6",
                 "import-fresh": "^3.0.0",
                 "imurmurhash": "^0.1.4",
-                "inquirer": "^6.4.1",
+                "inquirer": "^7.0.0",
                 "is-glob": "^4.0.0",
                 "js-yaml": "^3.13.1",
                 "json-stable-stringify-without-jsonify": "^1.0.1",
@@ -373,7 +352,7 @@
                 "minimatch": "^3.0.4",
                 "mkdirp": "^0.5.1",
                 "natural-compare": "^1.4.0",
-                "optionator": "^0.8.2",
+                "optionator": "^0.8.3",
                 "progress": "^2.0.0",
                 "regexpp": "^2.0.1",
                 "semver": "^6.1.2",
@@ -486,9 +465,9 @@
             "dev": true
         },
         "figures": {
-            "version": "2.0.0",
-            "resolved": "https://registry.npmjs.org/figures/-/figures-2.0.0.tgz",
-            "integrity": "sha1-OrGi0qYsi/tDGgyUy3l6L84nyWI=",
+            "version": "3.1.0",
+            "resolved": "https://registry.npmjs.org/figures/-/figures-3.1.0.tgz",
+            "integrity": "sha512-ravh8VRXqHuMvZt/d8GblBeqDMkdJMBdv/2KntFH+ra5MXkO7nxNKpzQ3n6QD/2da1kH0aWmNISdvhM7gl2gVg==",
             "dev": true,
             "requires": {
                 "escape-string-regexp": "^1.0.5"
@@ -520,33 +499,24 @@
             "integrity": "sha512-a1hQMktqW9Nmqr5aktAux3JMNqaucxGcjtjWnZLHX7yyPCmlSV3M54nGYbqT8K+0GhF3NBgmJCc3ma+WOgX8Jg==",
             "dev": true
         },
-        "for-each": {
-            "version": "0.3.3",
-            "resolved": "https://registry.npmjs.org/for-each/-/for-each-0.3.3.tgz",
-            "integrity": "sha512-jqYfLp7mo9vIyQf8ykW2v7A+2N4QjeCeI5+Dz9XraiO1ign81wjiH7Fb9vSOWvQfNtmSa4H2RoQTrrXivdUZmw==",
-            "dev": true,
-            "requires": {
-                "is-callable": "^1.1.3"
-            }
-        },
         "fs.realpath": {
             "version": "1.0.0",
             "resolved": "https://registry.npmjs.org/fs.realpath/-/fs.realpath-1.0.0.tgz",
             "integrity": "sha1-FQStJSMVjKpA20onh8sBQRmU6k8=",
             "dev": true
         },
-        "function-bind": {
-            "version": "1.1.1",
-            "resolved": "https://registry.npmjs.org/function-bind/-/function-bind-1.1.1.tgz",
-            "integrity": "sha512-yIovAzMX49sF8Yl58fSCWJ5svSLuaibPxXQJFLmBObTuCr0Mf1KiPopGM9NiFjiYBCbfaa2Fh6breQ6ANVTI0A==",
-            "dev": true
-        },
         "functional-red-black-tree": {
             "version": "1.0.1",
             "resolved": "https://registry.npmjs.org/functional-red-black-tree/-/functional-red-black-tree-1.0.1.tgz",
             "integrity": "sha1-GwqzvVU7Kg1jmdKcDj6gslIHgyc=",
             "dev": true
         },
+        "get-func-name": {
+            "version": "2.0.0",
+            "resolved": "https://registry.npmjs.org/get-func-name/-/get-func-name-2.0.0.tgz",
+            "integrity": "sha1-6td0q+5y4gQJQzoGY2YCPdaIekE=",
+            "dev": true
+        },
         "glob": {
             "version": "7.1.6",
             "resolved": "https://registry.npmjs.org/glob/-/glob-7.1.6.tgz",
@@ -571,18 +541,12 @@
             }
         },
         "globals": {
-            "version": "11.12.0",
-            "resolved": "https://registry.npmjs.org/globals/-/globals-11.12.0.tgz",
-            "integrity": "sha512-WOBp/EEGUiIsJSp7wcv/y6MO+lV9UoncWqxuFfm8eBwzWNgyfBd6Gz+IeKQ9jCmyhoH99g15M3T+QaVHFjizVA==",
-            "dev": true
-        },
-        "has": {
-            "version": "1.0.3",
-            "resolved": "https://registry.npmjs.org/has/-/has-1.0.3.tgz",
-            "integrity": "sha512-f2dvO0VU6Oej7RkWJGrehjbzMAjFp5/VKPp5tTpWIV4JHHZK1/BxbFRtf/siA2SWTe09caDmVtYYzWEIbBS4zw==",
+            "version": "12.3.0",
+            "resolved": "https://registry.npmjs.org/globals/-/globals-12.3.0.tgz",
+            "integrity": "sha512-wAfjdLgFsPZsklLJvOBUBmzYE8/CwhEqSBEMRXA3qxIiNtyqvjYurAtIfDh6chlEPUfmTY3MnZh5Hfh4q0UlIw==",
             "dev": true,
             "requires": {
-                "function-bind": "^1.1.1"
+                "type-fest": "^0.8.1"
             }
         },
         "has-flag": {
@@ -591,12 +555,6 @@
             "integrity": "sha1-tdRU3CGZriJWmfNGfloH87lVuv0=",
             "dev": true
         },
-        "has-symbols": {
-            "version": "1.0.1",
-            "resolved": "https://registry.npmjs.org/has-symbols/-/has-symbols-1.0.1.tgz",
-            "integrity": "sha512-PLcsoqu++dmEIZB+6totNFKq/7Do+Z0u4oT0zKOJNl3lYK6vGwwu2hjHs+68OEZbTjiUE9bgOABXbP/GvrS0Kg==",
-            "dev": true
-        },
         "iconv-lite": {
             "version": "0.4.24",
             "resolved": "https://registry.npmjs.org/iconv-lite/-/iconv-lite-0.4.24.tgz",
@@ -645,38 +603,26 @@
             "dev": true
         },
         "inquirer": {
-            "version": "6.5.2",
-            "resolved": "https://registry.npmjs.org/inquirer/-/inquirer-6.5.2.tgz",
-            "integrity": "sha512-cntlB5ghuB0iuO65Ovoi8ogLHiWGs/5yNrtUcKjFhSSiVeAIVpD7koaSU9RM8mpXw5YDi9RdYXGQMaOURB7ycQ==",
+            "version": "7.0.3",
+            "resolved": "https://registry.npmjs.org/inquirer/-/inquirer-7.0.3.tgz",
+            "integrity": "sha512-+OiOVeVydu4hnCGLCSX+wedovR/Yzskv9BFqUNNKq9uU2qg7LCcCo3R86S2E7WLo0y/x2pnEZfZe1CoYnORUAw==",
             "dev": true,
             "requires": {
-                "ansi-escapes": "^3.2.0",
+                "ansi-escapes": "^4.2.1",
                 "chalk": "^2.4.2",
-                "cli-cursor": "^2.1.0",
+                "cli-cursor": "^3.1.0",
                 "cli-width": "^2.0.0",
                 "external-editor": "^3.0.3",
-                "figures": "^2.0.0",
-                "lodash": "^4.17.12",
-                "mute-stream": "0.0.7",
+                "figures": "^3.0.0",
+                "lodash": "^4.17.15",
+                "mute-stream": "0.0.8",
                 "run-async": "^2.2.0",
-                "rxjs": "^6.4.0",
-                "string-width": "^2.1.0",
+                "rxjs": "^6.5.3",
+                "string-width": "^4.1.0",
                 "strip-ansi": "^5.1.0",
                 "through": "^2.3.6"
             }
         },
-        "is-callable": {
-            "version": "1.1.5",
-            "resolved": "https://registry.npmjs.org/is-callable/-/is-callable-1.1.5.tgz",
-            "integrity": "sha512-ESKv5sMCJB2jnHTWZ3O5itG+O128Hsus4K4Qh1h2/cgn2vbgnLSVqfV46AeJA9D5EeeLa9w81KUXMtn34zhX+Q==",
-            "dev": true
-        },
-        "is-date-object": {
-            "version": "1.0.2",
-            "resolved": "https://registry.npmjs.org/is-date-object/-/is-date-object-1.0.2.tgz",
-            "integrity": "sha512-USlDT524woQ08aoZFzh3/Z6ch9Y/EWXEHQ/AaRN0SkKq4t2Jw2R2339tSXmwuVoY7LLlBCbOIlx2myP/L5zk0g==",
-            "dev": true
-        },
         "is-extglob": {
             "version": "2.1.1",
             "resolved": "https://registry.npmjs.org/is-extglob/-/is-extglob-2.1.1.tgz",
@@ -684,9 +630,9 @@
             "dev": true
         },
         "is-fullwidth-code-point": {
-            "version": "2.0.0",
-            "resolved": "https://registry.npmjs.org/is-fullwidth-code-point/-/is-fullwidth-code-point-2.0.0.tgz",
-            "integrity": "sha1-o7MKXE8ZkYMWeqq5O+764937ZU8=",
+            "version": "3.0.0",
+            "resolved": "https://registry.npmjs.org/is-fullwidth-code-point/-/is-fullwidth-code-point-3.0.0.tgz",
+            "integrity": "sha512-zymm5+u+sCsSWyD9qNaejV3DFvhCKclKdizYaJUuHA83RLjb7nSuGnddCHGv0hk+KY7BMAlsWeK4Ueg6EV6XQg==",
             "dev": true
         },
         "is-glob": {
@@ -704,24 +650,6 @@
             "integrity": "sha1-eaKp7OfwlugPNtKy87wWwf9L8/o=",
             "dev": true
         },
-        "is-regex": {
-            "version": "1.0.5",
-            "resolved": "https://registry.npmjs.org/is-regex/-/is-regex-1.0.5.tgz",
-            "integrity": "sha512-vlKW17SNq44owv5AQR3Cq0bQPEb8+kF3UKZ2fiZNOWtztYE5i0CzCZxFDwO58qAOWtxdBRVO/V5Qin1wjCqFYQ==",
-            "dev": true,
-            "requires": {
-                "has": "^1.0.3"
-            }
-        },
-        "is-symbol": {
-            "version": "1.0.3",
-            "resolved": "https://registry.npmjs.org/is-symbol/-/is-symbol-1.0.3.tgz",
-            "integrity": "sha512-OwijhaRSgqvhm/0ZdAcXNZt9lYdKFpcRDT5ULUuYXPoT794UNOdU+gpT6Rzo7b4V2HUl/op6GqY894AZwv9faQ==",
-            "dev": true,
-            "requires": {
-                "has-symbols": "^1.0.1"
-            }
-        },
         "isexe": {
             "version": "2.0.0",
             "resolved": "https://registry.npmjs.org/isexe/-/isexe-2.0.0.tgz",
@@ -773,9 +701,9 @@
             "dev": true
         },
         "mimic-fn": {
-            "version": "1.2.0",
-            "resolved": "https://registry.npmjs.org/mimic-fn/-/mimic-fn-1.2.0.tgz",
-            "integrity": "sha512-jf84uxzwiuiIVKiOLpfYk7N46TSy8ubTonmneY9vrpHNAnp0QBt2BxWV9dO3/j+BoVAb+a5G6YDPW3M5HOdMWQ==",
+            "version": "2.1.0",
+            "resolved": "https://registry.npmjs.org/mimic-fn/-/mimic-fn-2.1.0.tgz",
+            "integrity": "sha512-OqbOk5oEQeAZ8WXWydlu9HJjz9WVdEIvamMCcXmuqUYjTknH/sqsWvhQ3vgwKFRR1HpjvNBKQ37nbJgYzGqGcg==",
             "dev": true
         },
         "minimatch": {
@@ -809,9 +737,9 @@
             "dev": true
         },
         "mute-stream": {
-            "version": "0.0.7",
-            "resolved": "https://registry.npmjs.org/mute-stream/-/mute-stream-0.0.7.tgz",
-            "integrity": "sha1-MHXOk7whuPq0PhvE2n6BFe0ee6s=",
+            "version": "0.0.8",
+            "resolved": "https://registry.npmjs.org/mute-stream/-/mute-stream-0.0.8.tgz",
+            "integrity": "sha512-nnbWWOkoWyUsTjKrhgD0dcz22mdkSnpYqbEjIm2nhwhuxlSkpywJmBo8h0ZqJdkp73mb90SssHkN4rsRaBAfAA==",
             "dev": true
         },
         "natural-compare": {
@@ -826,30 +754,6 @@
             "integrity": "sha512-1nh45deeb5olNY7eX82BkPO7SSxR5SSYJiPTrTdFUVYwAl8CKMA5N9PjTYkHiRjisVcxcQ1HXdLhx2qxxJzLNQ==",
             "dev": true
         },
-        "object-inspect": {
-            "version": "1.6.0",
-            "resolved": "https://registry.npmjs.org/object-inspect/-/object-inspect-1.6.0.tgz",
-            "integrity": "sha512-GJzfBZ6DgDAmnuaM3104jR4s1Myxr3Y3zfIyN4z3UdqN69oSRacNK8UhnobDdC+7J2AHCjGwxQubNJfE70SXXQ==",
-            "dev": true
-        },
-        "object-keys": {
-            "version": "1.1.1",
-            "resolved": "https://registry.npmjs.org/object-keys/-/object-keys-1.1.1.tgz",
-            "integrity": "sha512-NuAESUOUMrlIXOfHKzD6bpPu3tYt3xvjNdRIQ+FeT0lNb4K8WR70CaDxhuNguS2XG+GjkyMwOzsN5ZktImfhLA==",
-            "dev": true
-        },
-        "object.assign": {
-            "version": "4.1.0",
-            "resolved": "https://registry.npmjs.org/object.assign/-/object.assign-4.1.0.tgz",
-            "integrity": "sha512-exHJeq6kBKj58mqGyTQ9DFvrZC/eR6OwxzoM9YRoGBqrXYonaFyGiFMuc9VZrXf7DarreEwMpurG3dd+CNyW5w==",
-            "dev": true,
-            "requires": {
-                "define-properties": "^1.1.2",
-                "function-bind": "^1.1.1",
-                "has-symbols": "^1.0.0",
-                "object-keys": "^1.0.11"
-            }
-        },
         "once": {
             "version": "1.4.0",
             "resolved": "https://registry.npmjs.org/once/-/once-1.4.0.tgz",
@@ -860,12 +764,12 @@
             }
         },
         "onetime": {
-            "version": "2.0.1",
-            "resolved": "https://registry.npmjs.org/onetime/-/onetime-2.0.1.tgz",
-            "integrity": "sha1-BnQoIw/WdEOyeUsiu6UotoZ5YtQ=",
+            "version": "5.1.0",
+            "resolved": "https://registry.npmjs.org/onetime/-/onetime-5.1.0.tgz",
+            "integrity": "sha512-5NcSkPHhwTVFIQN+TUqXoS5+dlElHXdpAWu9I0HP20YOtIi+aZ0Ct82jdlILDxjLEAWwvm+qj1m6aEtsDVmm6Q==",
             "dev": true,
             "requires": {
-                "mimic-fn": "^1.0.0"
+                "mimic-fn": "^2.1.0"
             }
         },
         "optionator": {
@@ -915,6 +819,12 @@
             "integrity": "sha512-GSmOT2EbHrINBf9SR7CDELwlJ8AENk3Qn7OikK4nFYAu3Ote2+JYNVvkpAEQm3/TLNEJFD/xZJjzyxg3KBWOzw==",
             "dev": true
         },
+        "pathval": {
+            "version": "1.1.0",
+            "resolved": "https://registry.npmjs.org/pathval/-/pathval-1.1.0.tgz",
+            "integrity": "sha1-uULm1L3mUwBe9rcTYd74cn0GReA=",
+            "dev": true
+        },
         "prelude-ls": {
             "version": "1.1.2",
             "resolved": "https://registry.npmjs.org/prelude-ls/-/prelude-ls-1.1.2.tgz",
@@ -933,22 +843,22 @@
             "integrity": "sha512-XRsRjdf+j5ml+y/6GKHPZbrF/8p2Yga0JPtdqTIY2Xe5ohJPD9saDJJLPvp9+NSBprVvevdXZybnj2cv8OEd0A==",
             "dev": true
         },
+        "regenerator-runtime": {
+            "version": "0.13.3",
+            "resolved": "https://registry.npmjs.org/regenerator-runtime/-/regenerator-runtime-0.13.3.tgz",
+            "integrity": "sha512-naKIZz2GQ8JWh///G7L3X6LaQUAMp2lvb1rvwwsURe/VXwD6VMfr+/1NuNw3ag8v2kY1aQ/go5SNn79O9JU7yw==",
+            "dev": true
+        },
         "regexpp": {
             "version": "2.0.1",
             "resolved": "https://registry.npmjs.org/regexpp/-/regexpp-2.0.1.tgz",
             "integrity": "sha512-lv0M6+TkDVniA3aD1Eg0DVpfU/booSu7Eev3TDO/mZKHBfVjgCGTV4t4buppESEYDtkArYFOxTJWv6S5C+iaNw==",
             "dev": true
         },
-        "requirejs": {
-            "version": "2.3.6",
-            "resolved": "https://registry.npmjs.org/requirejs/-/requirejs-2.3.6.tgz",
-            "integrity": "sha512-ipEzlWQe6RK3jkzikgCupiTbTvm4S0/CAU5GlgptkN5SO6F3u0UD0K18wy6ErDqiCyP4J4YYe1HuAShvsxePLg==",
-            "dev": true
-        },
         "resolve": {
-            "version": "1.11.1",
-            "resolved": "https://registry.npmjs.org/resolve/-/resolve-1.11.1.tgz",
-            "integrity": "sha512-vIpgF6wfuJOZI7KKKSP+HmiKggadPQAdsp5HiC1mvqnfp0gF1vdwgBWZIdrVft9pgqoMFQN+R7BSWZiBxx+BBw==",
+            "version": "1.15.0",
+            "resolved": "https://registry.npmjs.org/resolve/-/resolve-1.15.0.tgz",
+            "integrity": "sha512-+hTmAldEGE80U2wJJDC1lebb5jWqvTYAfm3YZ1ckk1gBr0MnCqUKlwK1e+anaFljIl+F5tR5IoZcm4ZDA1zMQw==",
             "dev": true,
             "requires": {
                 "path-parse": "^1.0.6"
@@ -961,24 +871,15 @@
             "dev": true
         },
         "restore-cursor": {
-            "version": "2.0.0",
-            "resolved": "https://registry.npmjs.org/restore-cursor/-/restore-cursor-2.0.0.tgz",
-            "integrity": "sha1-n37ih/gv0ybU/RYpI9YhKe7g368=",
+            "version": "3.1.0",
+            "resolved": "https://registry.npmjs.org/restore-cursor/-/restore-cursor-3.1.0.tgz",
+            "integrity": "sha512-l+sSefzHpj5qimhFSE5a8nufZYAM3sBSVMAPtYkmC+4EH2anSGaEMXSD0izRQbu9nfyQ9y5JrVmp7E8oZrUjvA==",
             "dev": true,
             "requires": {
-                "onetime": "^2.0.0",
+                "onetime": "^5.1.0",
                 "signal-exit": "^3.0.2"
             }
         },
-        "resumer": {
-            "version": "0.0.0",
-            "resolved": "https://registry.npmjs.org/resumer/-/resumer-0.0.0.tgz",
-            "integrity": "sha1-8ej0YeQGS6Oegq883CqMiT0HZ1k=",
-            "dev": true,
-            "requires": {
-                "through": "~2.3.4"
-            }
-        },
         "rimraf": {
             "version": "2.6.3",
             "resolved": "https://registry.npmjs.org/rimraf/-/rimraf-2.6.3.tgz",
@@ -1048,6 +949,14 @@
                 "ansi-styles": "^3.2.0",
                 "astral-regex": "^1.0.0",
                 "is-fullwidth-code-point": "^2.0.0"
+            },
+            "dependencies": {
+                "is-fullwidth-code-point": {
+                    "version": "2.0.0",
+                    "resolved": "https://registry.npmjs.org/is-fullwidth-code-point/-/is-fullwidth-code-point-2.0.0.tgz",
+                    "integrity": "sha1-o7MKXE8ZkYMWeqq5O+764937ZU8=",
+                    "dev": true
+                }
             }
         },
         "sprintf-js": {
@@ -1057,57 +966,27 @@
             "dev": true
         },
         "string-width": {
-            "version": "2.1.1",
-            "resolved": "https://registry.npmjs.org/string-width/-/string-width-2.1.1.tgz",
-            "integrity": "sha512-nOqH59deCq9SRHlxq1Aw85Jnt4w6KvLKqWVik6oA9ZklXLNIOlqg4F2yrT1MVaTjAqvVwdfeZ7w7aCvJD7ugkw==",
+            "version": "4.2.0",
+            "resolved": "https://registry.npmjs.org/string-width/-/string-width-4.2.0.tgz",
+            "integrity": "sha512-zUz5JD+tgqtuDjMhwIg5uFVV3dtqZ9yQJlZVfq4I01/K5Paj5UHj7VyrQOJvzawSVlKpObApbfD0Ed6yJc+1eg==",
             "dev": true,
             "requires": {
-                "is-fullwidth-code-point": "^2.0.0",
-                "strip-ansi": "^4.0.0"
+                "emoji-regex": "^8.0.0",
+                "is-fullwidth-code-point": "^3.0.0",
+                "strip-ansi": "^6.0.0"
             },
             "dependencies": {
                 "strip-ansi": {
-                    "version": "4.0.0",
-                    "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-4.0.0.tgz",
-                    "integrity": "sha1-qEeQIusaw2iocTibY1JixQXuNo8=",
+                    "version": "6.0.0",
+                    "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-6.0.0.tgz",
+                    "integrity": "sha512-AuvKTrTfQNYNIctbR1K/YGTR1756GycPsg7b9bdV9Duqur4gv6aKqHXah67Z8ImS7WEz5QVcOtlfW2rZEugt6w==",
                     "dev": true,
                     "requires": {
-                        "ansi-regex": "^3.0.0"
+                        "ansi-regex": "^5.0.0"
                     }
                 }
             }
         },
-        "string.prototype.trim": {
-            "version": "1.1.2",
-            "resolved": "https://registry.npmjs.org/string.prototype.trim/-/string.prototype.trim-1.1.2.tgz",
-            "integrity": "sha1-0E3iyJ4Tf019IG8Ia17S+ua+jOo=",
-            "dev": true,
-            "requires": {
-                "define-properties": "^1.1.2",
-                "es-abstract": "^1.5.0",
-                "function-bind": "^1.0.2"
-            }
-        },
-        "string.prototype.trimleft": {
-            "version": "2.1.1",
-            "resolved": "https://registry.npmjs.org/string.prototype.trimleft/-/string.prototype.trimleft-2.1.1.tgz",
-            "integrity": "sha512-iu2AGd3PuP5Rp7x2kEZCrB2Nf41ehzh+goo8TV7z8/XDBbsvc6HQIlUl9RjkZ4oyrW1XM5UwlGl1oVEaDjg6Ag==",
-            "dev": true,
-            "requires": {
-                "define-properties": "^1.1.3",
-                "function-bind": "^1.1.1"
-            }
-        },
-        "string.prototype.trimright": {
-            "version": "2.1.1",
-            "resolved": "https://registry.npmjs.org/string.prototype.trimright/-/string.prototype.trimright-2.1.1.tgz",
-            "integrity": "sha512-qFvWL3/+QIgZXVmJBfpHmxLB7xsUXz6HsUmP8+5dRaC3Q7oKUv9Vo6aMCRZC1smrtyECFsIT30PqBJ1gTjAs+g==",
-            "dev": true,
-            "requires": {
-                "define-properties": "^1.1.3",
-                "function-bind": "^1.1.1"
-            }
-        },
         "strip-ansi": {
             "version": "5.2.0",
             "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-5.2.0.tgz",
@@ -1152,6 +1031,18 @@
                 "string-width": "^3.0.0"
             },
             "dependencies": {
+                "emoji-regex": {
+                    "version": "7.0.3",
+                    "resolved": "https://registry.npmjs.org/emoji-regex/-/emoji-regex-7.0.3.tgz",
+                    "integrity": "sha512-CwBLREIQ7LvYFB0WyRvwhq5N5qPhc6PMjD6bYggFlI5YyDgl+0vxq5VHbMOFqLg7hfWzmu8T5Z1QofhmTIhItA==",
+                    "dev": true
+                },
+                "is-fullwidth-code-point": {
+                    "version": "2.0.0",
+                    "resolved": "https://registry.npmjs.org/is-fullwidth-code-point/-/is-fullwidth-code-point-2.0.0.tgz",
+                    "integrity": "sha1-o7MKXE8ZkYMWeqq5O+764937ZU8=",
+                    "dev": true
+                },
                 "string-width": {
                     "version": "3.1.0",
                     "resolved": "https://registry.npmjs.org/string-width/-/string-width-3.1.0.tgz",
@@ -1165,35 +1056,6 @@
                 }
             }
         },
-        "tape": {
-            "version": "4.11.0",
-            "resolved": "https://registry.npmjs.org/tape/-/tape-4.11.0.tgz",
-            "integrity": "sha512-yixvDMX7q7JIs/omJSzSZrqulOV51EC9dK8dM0TzImTIkHWfe2/kFyL5v+d9C+SrCMaICk59ujsqFAVidDqDaA==",
-            "dev": true,
-            "requires": {
-                "deep-equal": "~1.0.1",
-                "defined": "~1.0.0",
-                "for-each": "~0.3.3",
-                "function-bind": "~1.1.1",
-                "glob": "~7.1.4",
-                "has": "~1.0.3",
-                "inherits": "~2.0.4",
-                "minimist": "~1.2.0",
-                "object-inspect": "~1.6.0",
-                "resolve": "~1.11.1",
-                "resumer": "~0.0.0",
-                "string.prototype.trim": "~1.1.2",
-                "through": "~2.3.8"
-            },
-            "dependencies": {
-                "minimist": {
-                    "version": "1.2.0",
-                    "resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
-                    "integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ=",
-                    "dev": true
-                }
-            }
-        },
         "text-table": {
             "version": "0.2.0",
             "resolved": "https://registry.npmjs.org/text-table/-/text-table-0.2.0.tgz",
@@ -1222,23 +1084,23 @@
             "dev": true
         },
         "tslint": {
-            "version": "5.18.0",
-            "resolved": "https://registry.npmjs.org/tslint/-/tslint-5.18.0.tgz",
-            "integrity": "sha512-Q3kXkuDEijQ37nXZZLKErssQVnwCV/+23gFEMROi8IlbaBG6tXqLPQJ5Wjcyt/yHPKBC+hD5SzuGaMora+ZS6w==",
+            "version": "6.0.0",
+            "resolved": "https://registry.npmjs.org/tslint/-/tslint-6.0.0.tgz",
+            "integrity": "sha512-9nLya8GBtlFmmFMW7oXXwoXS1NkrccqTqAtwXzdPV9e2mqSEvCki6iHL/Fbzi5oqbugshzgGPk7KBb2qNP1DSA==",
             "dev": true,
             "requires": {
                 "@babel/code-frame": "^7.0.0",
                 "builtin-modules": "^1.1.1",
                 "chalk": "^2.3.0",
                 "commander": "^2.12.1",
-                "diff": "^3.2.0",
+                "diff": "^4.0.1",
                 "glob": "^7.1.1",
                 "js-yaml": "^3.13.1",
                 "minimatch": "^3.0.4",
                 "mkdirp": "^0.5.1",
                 "resolve": "^1.3.2",
                 "semver": "^5.3.0",
-                "tslib": "^1.8.0",
+                "tslib": "^1.10.0",
                 "tsutils": "^2.29.0"
             },
             "dependencies": {
@@ -1268,10 +1130,22 @@
                 "prelude-ls": "~1.1.2"
             }
         },
+        "type-detect": {
+            "version": "4.0.8",
+            "resolved": "https://registry.npmjs.org/type-detect/-/type-detect-4.0.8.tgz",
+            "integrity": "sha512-0fr/mIH1dlO+x7TlcMy+bIDqKPsw/70tVyeHW787goQjhmqaZe10uwLujubK9q9Lg6Fiho1KUKDYz0Z7k7g5/g==",
+            "dev": true
+        },
+        "type-fest": {
+            "version": "0.8.1",
+            "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-0.8.1.tgz",
+            "integrity": "sha512-4dbzIzqvjtgiM5rw1k5rEHtBANKmdudhGyBEajN01fEyhaAIhsoKNy6y7+IN93IfpFtwY9iqi7kD+xwKhQsNJA==",
+            "dev": true
+        },
         "typescript": {
-            "version": "3.6.5",
-            "resolved": "https://registry.npmjs.org/typescript/-/typescript-3.6.5.tgz",
-            "integrity": "sha512-BEjlc0Z06ORZKbtcxGrIvvwYs5hAnuo6TKdNFL55frVDlB+na3z5bsLhFaIxmT+dPWgBIjMo6aNnTOgHHmHgiQ==",
+            "version": "3.7.5",
+            "resolved": "https://registry.npmjs.org/typescript/-/typescript-3.7.5.tgz",
+            "integrity": "sha512-/P5lkRXkWHNAbcJIiHPfRoKqyd7bsyCma1hZNUGfn20qm64T6ZBlrzprymeu918H+mB/0rIg2gGK/BXkhhYgBw==",
             "dev": true
         },
         "uri-js": {
@@ -1318,6 +1192,15 @@
             "requires": {
                 "mkdirp": "^0.5.1"
             }
+        },
+        "yaml": {
+            "version": "1.7.2",
+            "resolved": "https://registry.npmjs.org/yaml/-/yaml-1.7.2.tgz",
+            "integrity": "sha512-qXROVp90sb83XtAoqE8bP9RwAkTTZbugRUTm5YeFCBfNRPEp2YzTeqWiz7m5OORHzEvrA/qcGS8hp/E+MMROYw==",
+            "dev": true,
+            "requires": {
+                "@babel/runtime": "^7.6.3"
+            }
         }
     }
 }
diff --git a/package.json b/package.json
--- a/package.json
+++ b/package.json
@@ -1,14 +1,15 @@
 {
     "devDependencies": {
-        "@types/node": "8.0.0",
-        "@types/tape": "~4.2.33",
         "@types/requirejs": "2.1.31",
         "dojo": "1.16.0",
         "dojo-typings": "1.11.9",
-        "tape": "~4.13.0",
         "typescript": "~3.7.5",
         "eslint": "6.8.0",
         "tslint": "6.0.0",
-        "@implab/core-amd": "^1.3.2"
+        "@implab/core-amd": "^1.3.2",
+        "yaml": "~1.7.2",
+        "@types/yaml": "1.2.0",
+        "chai": "4.2.0",
+        "@types/chai": "4.1.3"
     }
 }
diff --git a/src/main/ts/NlsBundle.ts b/src/main/ts/NlsBundle.ts
--- a/src/main/ts/NlsBundle.ts
+++ b/src/main/ts/NlsBundle.ts
@@ -36,7 +36,7 @@ export class NlsBundle<T extends object>
 
     _cache: MapOf<PromiseOrValue<T>>;
 
-    constructor(defNls: T, locales: MapOf<any>) {
+    constructor(defNls: T, locales?: MapOf<any>) {
         this.default = defNls;
         this._locales = locales || {};
         this._cache = {};
@@ -51,17 +51,20 @@ export class NlsBundle<T extends object>
             a.push(x);
             locales.unshift(a.join("-"));
             return a;
-        }, []);
+        }, new Array<string>());
 
         return this._resolveLocale(locales);
     }
 
     _resolveLocale(locales: string[]): PromiseOrValue<T> {
         if (!locales.length)
-            return;
+            return this.default;
 
         const locale = locales.shift();
 
+        if (!locale)
+            return this._resolveLocale(locales);
+
         if (this._cache[locale])
             return this._cache[locale];
 
@@ -69,7 +72,7 @@ export class NlsBundle<T extends object>
         if (isCallback(data))
             data = data();
 
-        const parent = locales.length ? this._resolveLocale(locales) : this.default;
+        const parent = this._resolveLocale(locales);
 
         return this._cache[locale] = when(data, x => {
             return when(parent, y => this._cache[locale] = chainObjects(y, x));
diff --git a/src/main/ts/declare.ts b/src/main/ts/declare.ts
--- a/src/main/ts/declare.ts
+++ b/src/main/ts/declare.ts
@@ -132,7 +132,7 @@ export function djclass<T extends Abstra
 
         // proxy - фабрика для создания прокси-методов, которые внутри
         // себя вызовут this.inherited с правильными параметрами.
-        const proxy = (m: (...args: any[]) => any) => function () {
+        const proxy = (m: (...args: any[]) => any) => function (this: any) {
             return this.inherited(m, arguments);
         };
 
@@ -199,11 +199,11 @@ interface MemberBindSpec {
     getter?: boolean;
 }
 
-function isNodeBindSpec(v): v is NodeBindSpec {
+function isNodeBindSpec(v: any): v is NodeBindSpec {
     return "node" in v;
 }
 
-function isMemberBindSpec(v): v is MemberBindSpec {
+function isMemberBindSpec(v: any): v is MemberBindSpec {
     return "member" in v;
 }
 
@@ -220,7 +220,7 @@ export function bind(params: NodeBindSpe
     else if (isMemberBindSpec(params)) {
         return (target: any, name: string) => {
             target[name] = null;
-            target[makeSetterName(name)] = function (v) {
+            target[makeSetterName(name)] = function (v: any) {
                 this._set(name, v);
                 this[params.member].set(params.property, v);
             };
diff --git a/src/main/ts/djx/BuildContextBase.ts b/src/main/ts/djx/BuildContextBase.ts
--- a/src/main/ts/djx/BuildContextBase.ts
+++ b/src/main/ts/djx/BuildContextBase.ts
@@ -1,12 +1,12 @@
-import { isNull, mixin } from "@implab/core-amd/safe";
+import { isNull, mixin, argumentNotNull } from "@implab/core-amd/safe";
 import { isPlainObject, isNode, isBuildContext } from "./traits";
 
 export abstract class BuildContextBase {
     _attrs = {};
 
-    _children = [];
+    _children = new Array();
 
-    _created: boolean;
+    _created: boolean = false;
 
     visitNext(v: any) {
         if (isNull(v))
@@ -28,9 +28,6 @@ export abstract class BuildContextBase {
     }
 
     getChildDom(v: any) {
-        if (isNull(v))
-            return;
-
         const tv = typeof v;
         if (tv === "string" || tv === "number" || tv === "boolean" || v instanceof RegExp || v instanceof Date) {
             return document.createTextNode(v.toString());
@@ -48,8 +45,8 @@ export abstract class BuildContextBase {
     ensureCreated() {
         if (!this._created) {
             this._create(this._attrs, this._children);
-            this._children = null;
-            this._attrs = null;
+            this._children = [];
+            this._attrs = {};
             this._created = true;
         }
     }
diff --git a/src/main/ts/djx/DjxWidgetBase.ts b/src/main/ts/djx/DjxWidgetBase.ts
--- a/src/main/ts/djx/DjxWidgetBase.ts
+++ b/src/main/ts/djx/DjxWidgetBase.ts
@@ -17,23 +17,28 @@ export abstract class DjxWidgetBase exte
     _processTemplateNode<T extends (Element | Node | _WidgetBase)>(
         baseNode: T,
         getAttrFunc: (baseNode: T, attr: string) => string,
-        attachFunc: (node: T, type: string, func?: (...args: any[]) => any) => dojo.Handle
+        // tslint:disable-next-line: ban-types
+        attachFunc: (node: T, type: string, func?: Function) => dojo.Handle
     ): boolean {
         if (isNode(baseNode)) {
             const w = registry.byNode(baseNode);
             if (w) {
                 // from dijit/_WidgetsInTemplateMixin
                 this._processTemplateNode(w,
-                    (n, p) => n[p], // callback to get a property of a widget
+                    (n, p) => n.get(p), // callback to get a property of a widget
                     (widget, type, callback) => {
+                        if (!callback)
+                            throw new Error("The callback must be specified");
+
                         // callback to do data-dojo-attach-event to a widget
                         if (type in widget) {
                             // back-compat, remove for 2.0
-                            return widget.connect(widget, type, callback);
+                            return widget.connect(widget, type, callback as EventListener);
                         } else {
                             // 1.x may never hit this branch, but it's the default for 2.0
                             return widget.on(type, callback);
                         }
+
                     });
                 // don't process widgets internals
                 return false;
diff --git a/src/main/ts/djx/HtmlElementContext.ts b/src/main/ts/djx/HtmlElementContext.ts
--- a/src/main/ts/djx/HtmlElementContext.ts
+++ b/src/main/ts/djx/HtmlElementContext.ts
@@ -6,7 +6,7 @@ import { BuildContextBase } from "./Buil
 export class HtmlElementContext extends BuildContextBase {
     elementType: string;
 
-    _element: HTMLElement;
+    _element: HTMLElement | undefined;
 
     constructor(elementType: string) {
         argumentNotEmptyString(elementType, "elementType");
@@ -16,10 +16,15 @@ export class HtmlElementContext extends 
     }
 
     _addChild(child: any): void {
+        if (!this._element)
+            throw new Error("The HTML element isn't created");
         dom.place(this.getChildDom(child), this._element);
     }
 
     _setAttrs(attrs: object): void {
+        if (!this._element)
+            throw new Error("The HTML element isn't created");
+
         attr.set(this._element, attrs);
     }
 
@@ -31,6 +36,9 @@ export class HtmlElementContext extends 
     }
 
     _getDomElement() {
+        if (!this._element)
+            throw new Error("The HTML element isn't created");
+
         return this._element;
     }
 
diff --git a/src/main/ts/djx/WidgetContext.ts b/src/main/ts/djx/WidgetContext.ts
--- a/src/main/ts/djx/WidgetContext.ts
+++ b/src/main/ts/djx/WidgetContext.ts
@@ -7,7 +7,7 @@ import { BuildContextBase } from "./Buil
 export class WidgetContext extends BuildContextBase {
     widgetClass: _WidgetBaseConstructor;
 
-    _instance: _WidgetBase;
+    _instance: _WidgetBase | undefined;
 
     constructor(widgetClass: _WidgetBaseConstructor) {
         super();
@@ -17,14 +17,14 @@ export class WidgetContext extends Build
     }
 
     _addChild(child: any): void {
-        if (!this._instance.containerNode)
+        if (!this._instance || !this._instance.containerNode)
             throw new Error("Widget doesn't support adding children");
 
         dom.place(this.getChildDom(child), this._instance.containerNode);
     }
 
     _setAttrs(attrs: object): void {
-        this._instance.set(attrs);
+        this._instance?.set(attrs);
     }
 
     _create(attrs: object, children: any[]) {
@@ -34,6 +34,8 @@ export class WidgetContext extends Build
     }
 
     _getDomElement() {
+        if (!this._instance)
+            throw new Error("The instance of the widget isn't created");
         return this._instance.domNode;
     }
 
diff --git a/src/main/typings/declarations.d.ts b/src/main/typings/declarations.d.ts
new file mode 100644
diff --git a/src/test/ts/Tap.ts b/src/test/ts/Tap.ts
new file mode 100644
--- /dev/null
+++ b/src/test/ts/Tap.ts
@@ -0,0 +1,148 @@
+import { stringify } from "yaml";
+
+export interface TapWriter {
+    version(): void;
+    plan(n: number): void;
+    fail(e: any): void;
+    ok(msg: string): void;
+    skip(msg: string): void;
+    bailOut(msg: string): void;
+    comment(msg: string): void;
+    yaml(data: any): void;
+    end(): void;
+}
+
+enum TapState {
+    Init,
+    VersionWritten,
+    Ready,
+    ReadyWithoutPlan,
+    End
+}
+
+export abstract class AbstractTapWriter implements TapWriter {
+    private _state = TapState.Init;
+    private _version = 13;
+    private _testIndex = 1;
+
+    private _moveVersion() {
+        switch (this._state) {
+            case TapState.Init:
+                this._state = TapState.VersionWritten;
+                break;
+            default:
+                throw new Error("Invalid operation");
+        }
+
+    }
+
+    private _movePlan() {
+        switch (this._state) {
+            case TapState.Init:
+            case TapState.VersionWritten:
+                this._state = TapState.Ready;
+                break;
+            case TapState.ReadyWithoutPlan:
+                this._state = TapState.End;
+                break;
+            default:
+                throw new Error("Invalid operation");
+        }
+    }
+
+    private _moveTestResult() {
+        switch (this._state) {
+            case TapState.Init:
+            case TapState.VersionWritten:
+                this._state = TapState.ReadyWithoutPlan;
+                break;
+            case TapState.Ready:
+            case TapState.ReadyWithoutPlan:
+                break;
+            default:
+                throw new Error("Invalid operation");
+        }
+    }
+
+    private _moveEnd() {
+        switch (this._state) {
+            case TapState.End:
+                throw new Error("Invalid operation");
+            default:
+                this._state = TapState.End;
+        }
+    }
+
+    private _moveDiag() {
+        switch (this._state) {
+            case TapState.Init:
+            case TapState.VersionWritten:
+                this._state = TapState.ReadyWithoutPlan;
+                break;
+            case TapState.Ready:
+            case TapState.ReadyWithoutPlan:
+                break;
+            default:
+                throw new Error("Invalid operation");
+        }
+    }
+
+    version() {
+        this._moveVersion();
+
+        this._writeLine(`TAP version ${this._version}`);
+    }
+
+    plan(n: number) {
+        this._movePlan();
+
+        this._writeLine(`1..${n}`);
+    }
+
+    fail(e: any) {
+        this._moveTestResult();
+
+        this._writeText(`not ok ${this._testIndex} ${e}`);
+        this._testIndex++;
+    }
+
+    ok(msg: string) {
+        this._moveTestResult();
+
+        this._writeText(`ok ${this._testIndex} ${msg}`);
+        this._testIndex++;
+    }
+    skip(msg: string) {
+        this._moveTestResult();
+
+        this._writeText(`ok ${this._testIndex} # SKIPPED: ${msg}`);
+        this._testIndex++;
+    }
+    bailOut(msg: string) {
+        this._moveEnd();
+
+        this._writeText(`Bail out! ${msg}`);
+    }
+    comment(msg: string) {
+        this._moveDiag();
+
+        this._writeText(`# ${msg}`);
+    }
+    yaml(data: any) {
+        this._moveDiag();
+
+        this._writeLine("  ---");
+        stringify(data).split("\r\n?").forEach(line => this._writeLine("  " + line));
+        this._writeLine("  ...");
+    }
+    end() {
+        this._moveEnd();
+    }
+
+    private _writeText(text: string) {
+        text.split("\r\n?").forEach((line, i) => this._writeLine(i ? "# " + line : line));
+    }
+
+    abstract _writeLine(text: string): void;
+
+}
diff --git a/src/test/ts/TestTraits.ts b/src/test/ts/TestTraits.ts
--- a/src/test/ts/TestTraits.ts
+++ b/src/test/ts/TestTraits.ts
@@ -1,18 +1,21 @@
 import { IObservable, ICancellation, IDestroyable } from "@implab/core-amd/interfaces";
 import { Cancellation } from "@implab/core-amd/Cancellation";
 import { TraceEvent, LogLevel, WarnLevel, DebugLevel, TraceSource } from "@implab/core-amd/log/TraceSource";
-import * as tape from "tape";
 import { argumentNotNull, destroy } from "@implab/core-amd/safe";
+import { TapWriter } from "./Tap";
+
+
 
 export class TapeWriter implements IDestroyable {
-    private readonly _tape: tape.Test;
+
+    private readonly _t: TapWriter;
 
     private readonly _subscriptions = new Array<IDestroyable>();
     private _destroyed;
 
-    constructor(t: tape.Test) {
-        argumentNotNull(t, "tape");
-        this._tape = t;
+    constructor(t: TapWriter) {
+        argumentNotNull(t, "test");
+
     }
 
     writeEvents(source: IObservable<TraceEvent>, ct: ICancellation = Cancellation.none) {
@@ -27,13 +30,13 @@ export class TapeWriter implements IDest
 
     writeEvent(next: TraceEvent) {
         if (next.level >= DebugLevel) {
-            this._tape.comment(`DEBUG ${next.source.id} ${next}`);
+            this._t.comment(`DEBUG ${next.source.id} ${next}`);
         } else if (next.level >= LogLevel) {
-            this._tape.comment(`LOG   ${next.source.id} ${next}`);
+            this._t.comment(`LOG   ${next.source.id} ${next}`);
         } else if (next.level >= WarnLevel) {
-            this._tape.comment(`WARN  ${next.source.id} ${next}`);
+            this._t.comment(`WARN  ${next.source.id} ${next}`);
         } else {
-            this._tape.comment(`ERROR ${next.source.id} ${next}`);
+            this._t.comment(`ERROR ${next.source.id} ${next}`);
         }
     }
 
@@ -42,33 +45,13 @@ export class TapeWriter implements IDest
     }
 }
 
-export function test(name: string, cb: (t: tape.Test, trace: TraceSource) => any) {
-    tape(name, async t => {
-        const writer = new TapeWriter(t);
-
-        // this trace is not announced through the TraceSource global registry
-        const trace = new TraceSource(name);
-        trace.level = DebugLevel;
-        writer.writeEvents(trace.events);
-
-        const h = TraceSource.on(ts => {
-            ts.level = DebugLevel;
-            writer.writeEvents(ts.events);
-        });
+type TestCallback = (ok: (msg:string) => void, fail: (msg:string) => void, trace: TraceSource) => void;
+type AsyncTestCallback = (trace: TraceSource) => PromiseLike<void> | void;
 
-        try {
-            await cb(t, trace);
-        } catch (e) {
+export function test(name: string, cb: TestCallback | AsyncTestCallback) {
+    
+}
 
-            // verbose error information
-            // tslint:disable-next-line
-            console.error(e);
-            t.fail(e);
+export function run() {
 
-        } finally {
-            t.end();
-            destroy(writer);
-            destroy(h);
-        }
-    });
 }
diff --git a/src/test/ts/TextTapWriter.ts b/src/test/ts/TextTapWriter.ts
new file mode 100644
--- /dev/null
+++ b/src/test/ts/TextTapWriter.ts
@@ -0,0 +1,18 @@
+import { AbstractTapWriter } from "./Tap";
+import { TextWriter } from "@implab/core-amd/interfaces";
+
+export class TextTapWriter extends AbstractTapWriter {
+
+    private readonly _writer: TextWriter;
+
+    constructor(writer: TextWriter) {
+        super();
+
+        this._writer = writer;
+    }
+
+    _writeLine(text: string) {
+        this._writer.writeLine(text);
+    }
+
+}
\ No newline at end of file
diff --git a/src/test/ts/dummy.ts b/src/test/ts/dummy.ts
--- a/src/test/ts/dummy.ts
+++ b/src/test/ts/dummy.ts
@@ -1,10 +1,16 @@
-import * as tape from "tape";
+import { test } from "./TestTraits";
+import { delay } from "@implab/core-amd/safe";
+import { assert } from "chai";
 
-tape("simple", t => {
-    t.pass("sync assert");
+test("simple", (ok, fail, log) => {
     setTimeout(() => {
-        t.pass("async assert");
         // end should be called after the last assertion
-        t.end();
+        ok("async assert");
     }, 100);
 });
+
+test("simple", async log => {
+    await delay(0);
+
+    assert.ok(true); // everything is fine
+});
diff --git a/src/tsconfig.json b/src/tsconfig.json
--- a/src/tsconfig.json
+++ b/src/tsconfig.json
@@ -2,6 +2,7 @@
     "compilerOptions": {
         "moduleResolution": "node",
         "noEmitOnError": true,
+        "strict": true,
         "types": [],
         "experimentalDecorators": true,
         "jsxFactory": "createElement",