50 lines
1.5 KiB
JavaScript
50 lines
1.5 KiB
JavaScript
module.exports = class Backoff { // Internal library / utility for a class to retry a callback with delays, etc.
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constructor(min = 500, max = null) {
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this._timeoutId = null; // Setup internal vars
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this.fails = 0;
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this.min = min; // Setup args
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this.max = max ?? (min * 10);
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this.current = min;
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}
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get pending() { // If timeout currently set / waiting
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return this._timeoutId !== null;
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}
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succeed() { // Reset state on succeed
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this.current = this.min;
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this.fails = 0;
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this.cancel();
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}
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fail(callback) { // On fail, wait and callback
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const delay = this.current * 2;
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this.current = Math.min(this.current + delay, this.max);
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this.fails += 1; // Bump fails
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if (!callback) return this.current; // No callback given, skip rest of this
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if (this._timeoutId !== null) throw new Error('Callback already pending call'); // Timeout already set as waiting for another callback to call, throw error
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this._timeoutId = setTimeout(() => { // Set new timeout
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try {
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callback(); // Run callback
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} finally {
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this._timeoutId = null; // Stop tracking timeout internally as it's been executed
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}
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}, this.current);
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return this.current;
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}
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cancel() { // Cancel current timeout
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if (this._timeoutId === null) return; // If no timeout already, do nothing
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clearTimeout(this._timeoutId); // Stop timeout
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this_timeoutId = null; // Stop tracking timeout internally as it's been executed
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}
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}; |