50 lines
1.8 KiB
JavaScript
50 lines
1.8 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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var LazyValueState;
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(function (LazyValueState) {
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LazyValueState[LazyValueState["Uninitialized"] = 0] = "Uninitialized";
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LazyValueState[LazyValueState["Running"] = 1] = "Running";
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LazyValueState[LazyValueState["Completed"] = 2] = "Completed";
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})(LazyValueState || (LazyValueState = {}));
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class Lazy {
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constructor(executor) {
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this.executor = executor;
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this._state = LazyValueState.Uninitialized;
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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._state === LazyValueState.Uninitialized) {
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this._state = LazyValueState.Running;
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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._state = LazyValueState.Completed;
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}
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}
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else if (this._state === LazyValueState.Running) {
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throw new Error('Cannot read the value of a lazy that is being initialized');
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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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export { Lazy };
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