97 lines
1.9 KiB
JavaScript
97 lines
1.9 KiB
JavaScript
|
import AwaitValue from "./AwaitValue";
|
||
|
|
export default function AsyncGenerator(gen) {
|
||
|
|
var front, back;
|
||
|
|
|
||
|
|
function send(key, arg) {
|
||
|
|
return new Promise(function (resolve, reject) {
|
||
|
|
var request = {
|
||
|
|
key: key,
|
||
|
|
arg: arg,
|
||
|
|
resolve: resolve,
|
||
|
|
reject: reject,
|
||
|
|
next: null
|
||
|
|
};
|
||
|
|
|
||
|
|
if (back) {
|
||
|
|
back = back.next = request;
|
||
|
|
} else {
|
||
|
|
front = back = request;
|
||
|
|
resume(key, arg);
|
||
|
|
}
|
||
|
|
});
|
||
|
|
}
|
||
|
|
|
||
|
|
function resume(key, arg) {
|
||
|
|
try {
|
||
|
|
var result = gen[key](arg);
|
||
|
|
var value = result.value;
|
||
|
|
var wrappedAwait = value instanceof AwaitValue;
|
||
|
|
Promise.resolve(wrappedAwait ? value.wrapped : value).then(function (arg) {
|
||
|
|
if (wrappedAwait) {
|
||
|
|
resume("next", arg);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
settle(result.done ? "return" : "normal", arg);
|
||
|
|
}, function (err) {
|
||
|
|
resume("throw", err);
|
||
|
|
});
|
||
|
|
} catch (err) {
|
||
|
|
settle("throw", err);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
function settle(type, value) {
|
||
|
|
switch (type) {
|
||
|
|
case "return":
|
||
|
|
front.resolve({
|
||
|
|
value: value,
|
||
|
|
done: true
|
||
|
|
});
|
||
|
|
break;
|
||
|
|
|
||
|
|
case "throw":
|
||
|
|
front.reject(value);
|
||
|
|
break;
|
||
|
|
|
||
|
|
default:
|
||
|
|
front.resolve({
|
||
|
|
value: value,
|
||
|
|
done: false
|
||
|
|
});
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
front = front.next;
|
||
|
|
|
||
|
|
if (front) {
|
||
|
|
resume(front.key, front.arg);
|
||
|
|
} else {
|
||
|
|
back = null;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
this._invoke = send;
|
||
|
|
|
||
|
|
if (typeof gen["return"] !== "function") {
|
||
|
|
this["return"] = undefined;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if (typeof Symbol === "function" && Symbol.asyncIterator) {
|
||
|
|
AsyncGenerator.prototype[Symbol.asyncIterator] = function () {
|
||
|
|
return this;
|
||
|
|
};
|
||
|
|
}
|
||
|
|
|
||
|
|
AsyncGenerator.prototype.next = function (arg) {
|
||
|
|
return this._invoke("next", arg);
|
||
|
|
};
|
||
|
|
|
||
|
|
AsyncGenerator.prototype["throw"] = function (arg) {
|
||
|
|
return this._invoke("throw", arg);
|
||
|
|
};
|
||
|
|
|
||
|
|
AsyncGenerator.prototype["return"] = function (arg) {
|
||
|
|
return this._invoke("return", arg);
|
||
|
|
};
|