44 lines
1.6 KiB
JavaScript
44 lines
1.6 KiB
JavaScript
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export default function _asyncIterator(iterable) {
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var method,
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async,
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sync,
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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 {
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value: value,
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done: done
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};
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});
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}
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return AsyncFromSyncIterator = function AsyncFromSyncIterator(s) {
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this.s = s, this.n = s.next;
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}, AsyncFromSyncIterator.prototype = {
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s: null,
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n: null,
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next: function next() {
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return AsyncFromSyncIteratorContinuation(this.n.apply(this.s, arguments));
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},
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"return": function _return(value) {
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var ret = this.s["return"];
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return void 0 === ret ? Promise.resolve({
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value: value,
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done: !0
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}) : AsyncFromSyncIteratorContinuation(ret.apply(this.s, arguments));
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},
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"throw": function _throw(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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}, new AsyncFromSyncIterator(s);
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}
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