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