45 строки
1.4 KiB
JavaScript
45 строки
1.4 KiB
JavaScript
/**
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @flow strict-local
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* @format
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*/
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'use strict';
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const {polyfillGlobal} = require('../Utilities/PolyfillFunctions');
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const {hasNativeConstructor} = require('../Utilities/FeatureDetection');
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/**
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* Set up regenerator.
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* You can use this module directly, or just require InitializeCore.
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*/
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let hasNativeGenerator;
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try {
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// If this function was lowered by regenerator-transform, it will try to
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// access `global.regeneratorRuntime` which doesn't exist yet and will throw.
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hasNativeGenerator = hasNativeConstructor(function* () {},
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'GeneratorFunction');
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} catch {
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// In this case, we know generators are not provided natively.
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hasNativeGenerator = false;
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}
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// If generators are provided natively, which suggests that there was no
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// regenerator-transform, then there is no need to set up the runtime.
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if (!hasNativeGenerator) {
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polyfillGlobal('regeneratorRuntime', () => {
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// The require just sets up the global, so make sure when we first
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// invoke it the global does not exist
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delete global.regeneratorRuntime;
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// regenerator-runtime/runtime exports the regeneratorRuntime object, so we
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// can return it safely.
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return require('regenerator-runtime/runtime'); // flowlint-line untyped-import:off
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});
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}
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