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37 lines
1.7 KiB
37 lines
1.7 KiB
// https://github.com/tc39/proposal-iterator-helpers |
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var $ = require('../internals/export'); |
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var apply = require('../internals/function-apply'); |
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var anObject = require('../internals/an-object'); |
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var toObject = require('../internals/to-object'); |
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var isPrototypeOf = require('../internals/object-is-prototype-of'); |
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var AsyncIteratorPrototype = require('../internals/async-iterator-prototype'); |
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var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy'); |
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var getAsyncIterator = require('../internals/get-async-iterator'); |
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var getIterator = require('../internals/get-iterator'); |
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var getIteratorMethod = require('../internals/get-iterator-method'); |
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var getMethod = require('../internals/get-method'); |
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var wellKnownSymbol = require('../internals/well-known-symbol'); |
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var AsyncFromSyncIterator = require('../internals/async-from-sync-iterator'); |
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var ASYNC_ITERATOR = wellKnownSymbol('asyncIterator'); |
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var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise, args) { |
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return anObject(apply(this.next, this.iterator, args)); |
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}, true); |
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$({ target: 'AsyncIterator', stat: true, forced: true }, { |
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from: function from(O) { |
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var object = toObject(O); |
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var usingIterator = getMethod(object, ASYNC_ITERATOR); |
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var iterator; |
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if (usingIterator) { |
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iterator = getAsyncIterator(object, usingIterator); |
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if (isPrototypeOf(AsyncIteratorPrototype, iterator)) return iterator; |
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} |
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if (iterator === undefined) { |
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usingIterator = getIteratorMethod(object); |
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if (usingIterator) return new AsyncFromSyncIterator(getIterator(object, usingIterator)); |
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} |
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return new AsyncIteratorProxy({ iterator: iterator !== undefined ? iterator : object }); |
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} |
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});
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