将
SharedWorker
添加到 @angular/cli >1.2
生成的项目的具体步骤是什么。我希望 SharedWorker 在 TypeScript 中定义(具有完整/正确的类型定义编辑器支持),与主项目共享接口,并与主项目一起持续编译和测试。
我还没有发现描述如何修改 cli 生成的项目以包含
Worker
或 SharedWorker
的示例或博客文章。但是,有几篇文章(例如 this 一篇)展示了如何转换整个 cli 生成的项目以将其作为 Web Worker 运行。但这不是我的用例。
我想将与 Lovefield 数据库的交互限制在与主应用程序不同的进程中运行的
SharedWorker
。
虽然我已经尝试了一些尝试来解决这个问题,但我还没有取得太大进展。希望有人可以节省我(和未来的读者)很多时间。
我按照以下步骤让它工作:
src\app\shared-worker
创建包含以下内容的文件
src\app\shared-worker\shared-worker.d.ts
:
SharedWorker 定义
declare module SharedWorker {
interface AbstractWorker extends EventTarget {
onerror: (ev: ErrorEvent) => any;
}
export interface SharedWorker extends AbstractWorker {
port: MessagePort;
onconnect: (messageEvent: MessageEvent) => void;
}
}
declare var SharedWorker: {
prototype: SharedWorker.SharedWorker;
new(stringUrl: string, name?: string): SharedWorker.SharedWorker;
};
// Merely added the onconnect() method to the file provied via:
// npm install --save-dev retyped-sharedworker-tsd-ambient
// Definitions by: Toshiya Nakakura <https://github.com/nakakura>
使用以下演示内容创建文件
src\app\shared-worker\shared-worker.ts
:
共享工作者来源
/// <reference path=".\shared-worker.d.ts" />
(<any>self).onconnect = (connectEvent: MessageEvent) => {
const messagePort: MessagePort = (connectEvent.ports as MessagePort[])[0];
messagePort.onmessage = function (messageEvent: MessageEvent) {
const workerResult: number = messageEvent.data.firstNumber * messageEvent.data.secondNumber;
messagePort.postMessage(workerResult);
};
};
更新
src\app\app.component.ts
如下:
应用组件
import { Component, OnInit, ChangeDetectorRef } from '@angular/core';
import { Subject } from 'rxjs/Subject';
import { Observable } from 'rxjs/Observable';
@Component({
selector: 'app-root',
template: `
<input type="number" [(ngModel)]="firstNumber" />
<input type="number" [(ngModel)]="secondNumber" />
<hr /><button (click)="postMessageToSharedWorker()">Invoke Shared Worker</button>
<hr /><div>Result: {{result$ | async}}</div>`
})
export class AppComponent implements OnInit {
public firstNumber = 4;
public secondNumber = 8;
private resultSubject = new Subject<number>();
private sharedWorker: SharedWorker.SharedWorker;
public result$: Observable<number>;
public ngOnInit(): void {
this.result$ = this.resultSubject.asObservable();
if ('SharedWorker' in window) {
this.sharedWorker = new SharedWorker('app/shared-worker/shared-worker.js');
this.sharedWorker.port.onmessage = (messageEvent: MessageEvent) => {
this.resultSubject.next(messageEvent.data);
this.changeDetectorRef.detectChanges();
};
}
}
public postMessageToSharedWorker() {
if (!('SharedWorker' in window)) {
return;
}
this.sharedWorker.port.postMessage({ firstNumber: this.firstNumber, secondNumber: this.secondNumber });
}
constructor(private changeDetectorRef: ChangeDetectorRef) { }
}
将
"app/shared-worker/shared-worker.js"
添加到 apps.assets
中的 .angular-cli.json
concurrently
作为开发依赖项:npm i -D concurrently
创建
package.json
脚本
package.json
"wrk-w": "tsc --noLib --experimentalDecorators --watch node_modules/typescript/lib/lib.es6.d.ts src/app/shared-worker/shared-worker.d.ts src/app/shared-worker/shared-worker.ts",
"dev": "concurrently --kill-others \"npm run wrk-w\" \"npm run start\""
只需安装 @types/sharedworker 并将其添加到 tsconfig.app.json 的“types”数组选项中。
您可以使用 CLI 生成标准专用 Web Worker,然后更新代码以使用 Shared Worker。
new SharedWorker(new URL('./shared.worker', import.meta.url))
Angular CLI 将自动处理编译和捆绑工作文件。