38 lines
1.2 KiB
JavaScript
38 lines
1.2 KiB
JavaScript
/*---------------------------------------------------------------------------------------------
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* Copyright (c) Microsoft Corporation. All rights reserved.
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* Licensed under the MIT License. See License.txt in the project root for license information.
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*--------------------------------------------------------------------------------------------*/
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export class Lazy {
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constructor(executor) {
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this.executor = executor;
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this._didRun = false;
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}
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/**
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* Get the wrapped value.
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*
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* This will force evaluation of the lazy value if it has not been resolved yet. Lazy values are only
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* resolved once. `getValue` will re-throw exceptions that are hit while resolving the value
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*/
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get value() {
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if (!this._didRun) {
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try {
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this._value = this.executor();
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}
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catch (err) {
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this._error = err;
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}
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finally {
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this._didRun = true;
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}
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}
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if (this._error) {
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throw this._error;
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}
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return this._value;
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}
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/**
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* Get the wrapped value without forcing evaluation.
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*/
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get rawValue() { return this._value; }
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}
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