45 lines
1.7 KiB
JavaScript
45 lines
1.7 KiB
JavaScript
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export function _async_iterator(iterable) {
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var method, async, sync, retry = 2;
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for ("undefined" != typeof Symbol && (async = Symbol.asyncIterator, sync = Symbol.iterator); retry--;) {
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if (async && null != (method = iterable[async])) return method.call(iterable);
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if (sync && null != (method = iterable[sync])) return new AsyncFromSyncIterator(method.call(iterable));
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async = "@@asyncIterator", sync = "@@iterator";
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}
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throw new TypeError("Object is not async iterable");
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}
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function AsyncFromSyncIterator(s) {
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function AsyncFromSyncIteratorContinuation(r) {
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if (Object(r) !== r) return Promise.reject(new TypeError(r + " is not an object."));
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var done = r.done;
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return Promise.resolve(r.value).then(function(value) {
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return { value: value, done: done };
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});
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}
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return AsyncFromSyncIterator = function(s) {
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this.s = s, this.n = s.next;
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},
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AsyncFromSyncIterator.prototype = {
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s: null,
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n: null,
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next: function() {
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return AsyncFromSyncIteratorContinuation(this.n.apply(this.s, arguments));
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},
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return: function(value) {
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var ret = this.s.return;
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return void 0 === ret ? Promise.resolve({ value: value, done: !0 }) : AsyncFromSyncIteratorContinuation(ret.apply(this.s, arguments));
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},
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throw: function(value) {
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var thr = this.s.return;
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return void 0 === thr ? Promise.reject(value) : AsyncFromSyncIteratorContinuation(thr.apply(this.s, arguments));
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}
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},
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new AsyncFromSyncIterator(s);
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}
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export { _async_iterator as _ };
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