63 lines
1.9 KiB
JavaScript
63 lines
1.9 KiB
JavaScript
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import OverloadYield from "./OverloadYield.js";
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export default function AsyncGenerator(gen) {
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var front, back;
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function resume(key, arg) {
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try {
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var result = gen[key](arg),
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value = result.value,
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overloaded = value instanceof OverloadYield;
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Promise.resolve(overloaded ? value.v : value).then(function (arg) {
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if (overloaded) {
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var nextKey = "return" === key ? "return" : "next";
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if (!value.k || arg.done) return resume(nextKey, arg);
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arg = gen[nextKey](arg).value;
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}
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settle(result.done ? "return" : "normal", arg);
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}, function (err) {
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resume("throw", err);
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});
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} catch (err) {
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settle("throw", err);
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}
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}
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function settle(type, value) {
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switch (type) {
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case "return":
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front.resolve({
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value: value,
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done: !0
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});
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break;
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case "throw":
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front.reject(value);
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break;
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default:
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front.resolve({
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value: value,
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done: !1
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});
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}
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(front = front.next) ? resume(front.key, front.arg) : back = null;
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}
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this._invoke = function (key, arg) {
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return new Promise(function (resolve, reject) {
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var request = {
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key: key,
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arg: arg,
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resolve: resolve,
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reject: reject,
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next: null
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};
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back ? back = back.next = request : (front = back = request, resume(key, arg));
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});
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}, "function" != typeof gen["return"] && (this["return"] = void 0);
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}
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AsyncGenerator.prototype["function" == typeof Symbol && Symbol.asyncIterator || "@@asyncIterator"] = function () {
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return this;
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}, AsyncGenerator.prototype.next = function (arg) {
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return this._invoke("next", arg);
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}, AsyncGenerator.prototype["throw"] = function (arg) {
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return this._invoke("throw", arg);
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}, AsyncGenerator.prototype["return"] = function (arg) {
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return this._invoke("return", arg);
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};
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