implab/implabjs-core Commit - r159:130129fdbd20

Added safe.debounce function, this is a preview version

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r159:130129fdbd20

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package-lock.json +3 -3

                   }
                 },
                 "typescript": {
-                  "version": "3.6.4",
+                  "version": "4.1.5",
-                  "resolved": "https://registry.npmjs.org/typescript/-/typescript-3.6.4.tgz",
+                  "resolved": "https://registry.npmjs.org/typescript/-/typescript-4.1.5.tgz",
-                  "integrity": "sha512-unoCll1+l+YK4i4F8f22TaNVPRHcD9PA3yCuZ8g5e0qGqlVlJ/8FSateOLLSagn+Yg5+ZwuPkL8LFUc0Jcvksg==",
+                  "integrity": "sha512-6OSu9PTIzmn9TCDiovULTnET6BgXtDYL4Gg4szY+cGsc3JP1dQL8qvE8kShTRx1NIw4Q9IBHlwODjkjWEtMUyA==",
                   "dev": true
                 },
                 "uri-js": {

package.json +1 -1

                 "dojo-typings": "^1.11.9",
                 "requirejs": "latest",
                 "tape": "~4.11.0",
-                "typescript": "~3.6.4",
+                "typescript": "~4.1.5",
                 "eslint": "6.1.0",
                 "tslint": "5.18.0"
               }

src/main/ts/safe.ts +55 -1

@@ -5,6 +5,8 const _oid = typeof Symbol === "function
5	Symbol("__implab__oid__") :	5	Symbol("__implab__oid__") :
6	"__implab__oid__";	6	"__implab__oid__";
7		7
		8	function _noop() { }
		9
8	export function oid(instance: null \| undefined): undefined;	10	export function oid(instance: null \| undefined): undefined;
9	export function oid(instance: NonNullable<any>): string;	11	export function oid(instance: NonNullable<any>): string;
10	export function oid(instance: any): string \| undefined {	12	export function oid(instance: any): string \| undefined {
@@ -288,9 +290,14 export function delegate(target: any, _m
288	};	290	};
289	}	291	}
290		292
		293	/** Returns promise which will be resolved after the specified amount of time.
		294	*
		295	* @param timeMs The delay before the promise will be resolved in milliseconds.
		296	* @param ct Optional. A cancellation token for the operation.
		297	*/
291	export function delay(timeMs: number, ct = cancellationNone) {	298	export function delay(timeMs: number, ct = cancellationNone) {
292	ct.throwIfRequested();	299	ct.throwIfRequested();
293	return new Promise((resolve, reject) => {	300	return new Promise<void>((resolve, reject) => {
294	const h = ct.register(e => {	301	const h = ct.register(e => {
295	clearTimeout(id);	302	clearTimeout(id);
296	reject(e);	303	reject(e);
@@ -304,6 +311,53 export function delay(timeMs: number, ct
304	});	311	});
305	}	312	}
306		313
		314	export function debounce<T extends any[], R, This>(func: (this: This, ...args: T) => R \| PromiseLike<R>, wait: number) {
		315	let cancel: (e?: any) => void = _noop;
		316
		317	const fn = function executedFunction(this: This, ...args: T) {
		318	return new Promise<R>((resolve, reject) => {
		319
		320	// used to cleanup currently allocated resources
		321	const _cleanup = () => {
		322	cancel = _noop;
		323	clearTimeout(handle);
		324	};
		325
		326	// used in case of cancellation of the current operation
		327	const _cancel = (e: any) => {
		328	_cleanup();
		329	reject(e);
		330	};
		331
		332	// performs actual work
		333	const _later = () => {
		334	_cleanup();
		335	resolve(func.apply(this, args));
		336	};
		337
		338	// cancel previously queued operation
		339	if (cancel !== _noop)
		340	cancel(new Error("Operation cancelled due to debouncing"));
		341	cancel = _cancel;
		342
		343	const handle = setTimeout(_later, wait);
		344	});
		345	};
		346
		347	fn.cancel = (e?: any) => cancel(e);
		348
		349	fn.applyAsync = async (thisArg: This, args: T, ct: ICancellation) => {
		350	const h = ct.register(cancel);
		351	try {
		352	await fn.apply(thisArg, args);
		353	} finally {
		354	h.destroy();
		355	}
		356	};
		357
		358	return fn;
		359	}
		360
307	/** Returns resolved promise, awaiting this method will cause the asynchronous	361	/** Returns resolved promise, awaiting this method will cause the asynchronous
308	* completion of the rest of the code.	362	* completion of the rest of the code.
309	*/	363	*/

src/test/ts/tests/SafeTests.ts +62 -1

@@ -1,5 +1,6
1	import { Cancellation } from "../Cancellation";	1	import { Cancellation } from "../Cancellation";
2	import { first, isPromise, firstWhere, delay, nowait, notImplemented } from "../safe";	2	import { ICancellation } from "../interfaces";
		3	import { first, isPromise, firstWhere, delay, nowait, notImplemented, debounce, fork } from "../safe";
3	import { test } from "./TestTraits";	4	import { test } from "./TestTraits";
4		5
5	test("await delay test", async t => {	6	test("await delay test", async t => {
@@ -93,3 +94,63 test("sequemce test", async t => {
93	v = await new Promise(resolve => first(asyncSequence, resolve));	94	v = await new Promise(resolve => first(asyncSequence, resolve));
94	t.equal(v, "a", "The callback should be called for the first element");	95	t.equal(v, "a", "The callback should be called for the first element");
95	});	96	});
		97
		98	test("debounce tests", async (t, trace) => {
		99	let count = 0;
		100	let rejected = 0;
		101	function increment(step: number = 1) {
		102	count += step;
		103	return count;
		104	}
		105
		106	const f = debounce(increment, 100);
		107	f().then(undefined, () => rejected++);
		108	f().then(undefined, () => rejected++);
		109
		110	await f(1);
		111
		112	t.equal(rejected, 2, "Previous operations should be rejected");
		113	t.equal(count, 1, "The operation should run once");
		114
		115	const acc = debounce(
		116	(...values: number[]) => count = values.reduce((a, v) => v + a, count),
		117	100
		118	);
		119
		120	acc(1, 2, 3).catch(() => { });
		121	const result = acc(1, 2, 3);
		122	acc.cancel();
		123
		124	try {
		125	await result;
		126	t.notOk("fn.cancel() should make current operation to throw an exception");
		127	} catch {
		128	t.ok("fn.cancel() should make current operation to throw an exception");
		129	}
		130
		131	t.equal(count, 1, "fn.cancel() The operation should not run");
		132
		133	acc.cancel();
		134	await acc(1, 2);
		135	t.equal(count, 4, "The variable arguments list shoud be handled correctly");
		136
		137	// create cancellation token
		138	let cancel: (e?: any) => void = notImplemented;
		139	const ct = new Cancellation(c => cancel = c);
		140
		141	const d = debounce(async (ct2: ICancellation = Cancellation.none) => {
		142	ct2.throwIfRequested();
		143	trace.debug("do async increment");
		144	await fork();
		145	count++;
		146	return count;
		147	}, 0);
		148
		149	const p = d.applyAsync(null, [ct], ct).then(undefined, () => rejected++);
		150	cancel();
		151	await p;
		152
		153	t.equal(count, 4, "Cancellation token should prevent the function execution");
		154	t.equal(rejected, 3, "Cancellation token should reject operation");
		155
		156	});

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