# HG changeset patch
# User cin
# Date 2023-06-20 11:25:12
# Node ID 515d1b83ebdfaa93599451175055a94f711c079f
# Parent  9c8af9e9ba6fb5b8c414a1f85ef1978fc030531f

fixed undefined value when no checkboxes are selected in _FormMixin.

diff --git a/djx/src/main/ts/form/_FormMixin.ts b/djx/src/main/ts/form/_FormMixin.ts
--- a/djx/src/main/ts/form/_FormMixin.ts
+++ b/djx/src/main/ts/form/_FormMixin.ts
@@ -70,13 +70,15 @@ const collectDescendantFormWidgets = (ch
  */
 const _obj = (v: unknown) => (typeof v === "object" && v !== null ? v : {}) as Record<string, unknown>;
 
+type MergeHint = "array" | "append" | "unset";
+
 /** Combines the values
  * 
  * @param prev The previous value, `undefined` if none
  * @param value The new value to store
  * @param hint The hint how to combine values
  */
-const _combine = (prev: unknown, value: unknown, hint?: string) =>
+const _combine = (prev: unknown, value: unknown, hint?: MergeHint) =>
     // write the value as an array and append new values to it
     hint === "array" ? prev === undefined ? [value] : ([] as unknown[]).concat(prev, value) :
         // write the value as is and convert it the array when new values are appended
@@ -94,7 +96,7 @@ const _merge = (
     [prop, ...rest]: string[],
     obj: Record<string, unknown>,
     value: unknown,
-    hint?: string
+    hint?: MergeHint
 ): unknown => ({
     ...obj,
     [prop]: rest.length > 0 ?
@@ -111,7 +113,7 @@ const _merge = (
  * @param hint The hint how to store the value. The valid values are:
  *   `array`, `append`, `unset`.
  */
-const _assign = (name: string, obj: object, value: unknown, hint?: string) =>
+const _assign = (name: string, obj: object, value: unknown, hint?: MergeHint) =>
     _merge(name.split("."), _obj(obj), value, hint) as object;
 
 @djclass
@@ -221,6 +223,9 @@ abstract class _FormMixin extends djbase
                 }
             }
         });
+
+        // Note: no need to call this._set("value", ...) as the child updates will trigger onChange events
+        // which I am monitoring.
     }
 
     _getValueAttr() {
@@ -238,15 +243,17 @@ abstract class _FormMixin extends djbase
                                 return { name, value };
                             } else {
                                 // give radio widgets a default of null
-                                return { name, value: null, hint: "unset" };
+                                return { name, value: null, hint: "unset" as const};
                             }
                         } else {
                             // checkbox/toggle button
-                            if (value !== false)
-                                return { name, value, hint: "array" };
+                            return value !== false ?
+                                { name, value, hint: "array" as const} :
+                                // empty array when no checkboxes are selected
+                                { name, value: [], hint: "unset" as const }; 
                         }
                     } else {
-                        return { name, value, hint: "append" };
+                        return { name, value, hint: "append" as const};
                     }
                 }
                 return {};
@@ -294,7 +301,7 @@ abstract class _FormMixin extends djbase
             }
             this._onChangeDelayTimer = this.defer(() => {
                 this._onChangeDelayTimer = { remove: () => { } };
-                this._set("value", this.get("value"));
+                this._set("value", this._getValueAttr());
             }, 10);
         }
     }