current zone lost after await

[cl1ck]

With native V8 async/await the current zone is lost after awaiting an async function.

require('zone.js')

const delay = ms => new Promise(resolve => setTimeout(resolve, ms))

const test = async () => {
  console.log(Zone.current.name)
  await delay(100, 'test')
  console.log(Zone.current.name)
}

Zone.current.fork({
  name: 'test',
}).run(test)

output:

test
<root>

zone.js 0.8.5
node 7.4.0 with --harmony-async-await flag

[JiaLiPassion]

I am not sure my understanding is correct or not, it seems nodejs native async/await don't treat the async function as a bigger promise, so it will break zone in Promise.

for now, you can

const test = async () => {
  const zone = Zone.current;
  console.log(Zone.current.name)
  await delay(100, 'test')
  zone.run(() => {
    console.log(Zone.current.name)
  });
}

or use typescript instead

import './zone-node.js';
declare let Zone: any;
const delay = ms => 
new Promise(resolve => 
setTimeout(() => {
  resolve();
}, ms))

const test = async () => {
  console.log(Zone.current.name)
  await delay(100);
  console.log(Zone.current.name)
}

Zone.current.fork({
  name: 'test',
}).run(test);

it will compile to

"use strict";
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
    return new (P || (P = Promise))(function (resolve, reject) {
        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
        function step(result) { result.done ? resolve(result.value) : new P(function (resolve) { resolve(result.value); }).then(fulfilled, rejected); }
        step((generator = generator.apply(thisArg, _arguments)).next());
    });
};
var __generator = (this && this.__generator) || function (thisArg, body) {
    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t;
    return { next: verb(0), "throw": verb(1), "return": verb(2) };
    function verb(n) { return function (v) { return step([n, v]); }; }
    function step(op) {
        if (f) throw new TypeError("Generator is already executing.");
        while (_) try {
            if (f = 1, y && (t = y[op[0] & 2 ? "return" : op[0] ? "throw" : "next"]) && !(t = t.call(y, op[1])).done) return t;
            if (y = 0, t) op = [0, t.value];
            switch (op[0]) {
                case 0: case 1: t = op; break;
                case 4: _.label++; return { value: op[1], done: false };
                case 5: _.label++; y = op[1]; op = [0]; continue;
                case 7: op = _.ops.pop(); _.trys.pop(); continue;
                default:
                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
                    if (t[2]) _.ops.pop();
                    _.trys.pop(); continue;
            }
            op = body.call(thisArg, _);
        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
    }
};
var _this = this;
require("./zone-node.js");
var delay = function (ms) {
    return new Promise(function (resolve) {
        return setTimeout(function () {
            resolve();
        }, ms);
    });
};
var test = function () { return __awaiter(_this, void 0, void 0, function () {
    return __generator(this, function (_a) {
        switch (_a.label) {
            case 0:
                console.log(Zone.current.name);
                return [4 /*yield*/, delay(100)];
            case 1:
                _a.sent();
                console.log(Zone.current.name);
                return [2 /*return*/];
        }
    });
}); };
Zone.current.fork({
    name: 'test'
}).run(test);

typescript version async/await will keep zone in promise.

[amcdnl]

Looks like this has been resolved but not merged yet - https://github.com/angular/zone.js/issues/740

[JiaLiPassion]

close for duplicate