44d79e2c9a
- Unify test data for nonexistence of an object/string and collection. - Introduce more test through adding missing test data to existing tests. - Improve logic for checking absence of values to match tests. - Add missing tests for absent value validation. - Update documentation to include shared test functionality.
63 lines
1.9 KiB
TypeScript
63 lines
1.9 KiB
TypeScript
export type CallbackType = (..._: unknown[]) => void;
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export function throttle(
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callback: CallbackType,
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waitInMs: number,
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timer: ITimer = NodeTimer,
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): CallbackType {
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const throttler = new Throttler(timer, waitInMs, callback);
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return (...args: unknown[]) => throttler.invoke(...args);
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}
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// Allows aligning with both NodeJs (NodeJs.Timeout) and Window type (number)
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export type TimeoutType = ReturnType<typeof setTimeout>;
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export interface ITimer {
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setTimeout: (callback: () => void, ms: number) => TimeoutType;
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clearTimeout: (timeoutId: TimeoutType) => void;
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dateNow(): number;
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}
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const NodeTimer: ITimer = {
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setTimeout: (callback, ms) => setTimeout(callback, ms),
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clearTimeout: (timeoutId) => clearTimeout(timeoutId),
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dateNow: () => Date.now(),
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};
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interface IThrottler {
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invoke: CallbackType;
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}
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class Throttler implements IThrottler {
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private queuedExecutionId: TimeoutType;
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private previouslyRun: number;
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constructor(
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private readonly timer: ITimer,
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private readonly waitInMs: number,
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private readonly callback: CallbackType,
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) {
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if (!timer) { throw new Error('missing timer'); }
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if (!waitInMs) { throw new Error('missing delay'); }
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if (waitInMs < 0) { throw new Error('negative delay'); }
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if (!callback) { throw new Error('missing callback'); }
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}
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public invoke(...args: unknown[]): void {
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const now = this.timer.dateNow();
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if (this.queuedExecutionId !== undefined) {
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this.timer.clearTimeout(this.queuedExecutionId);
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this.queuedExecutionId = undefined;
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}
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if (!this.previouslyRun || (now - this.previouslyRun >= this.waitInMs)) {
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this.callback(...args);
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this.previouslyRun = now;
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} else {
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const nextCall = () => this.invoke(...args);
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const nextCallDelayInMs = this.waitInMs - (now - this.previouslyRun);
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this.queuedExecutionId = this.timer.setTimeout(nextCall, nextCallDelayInMs);
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}
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}
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}
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