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angular - Angular Elements - 未捕获的类型错误：无法构造“HTMLElement”

问题描述

我一直在尝试让 Angular 元素组件正常工作，因为我正在考虑在即将到来的项目中使用它们。

我遵循了许多教程（都非常相似），只是无法让它们工作。其中一个教程就是这个。

我有 Elements 项目的以下 package.json

        {
      "name": "angular-webcomponents-demo",
      "version": "0.0.0",
      "scripts": {
        "ng": "ng",
        "start": "ng serve",
        "build": "ng build",
        "test": "ng test",
        "lint": "ng lint",
        "e2e": "ng e2e",
        "build:elements": "ng build --prod --output-hashing none && node build-script.js"
      },
      "private": true,
      "dependencies": {
        "@angular/animations": "~7.2.0",
        "@angular/common": "~7.2.0",
        "@angular/compiler": "~7.2.0",
        "@angular/core": "~7.2.0",
        "@angular/elements": "^7.2.15",
        "@angular/forms": "~7.2.0",
        "@angular/platform-browser": "~7.2.0",
        "@angular/platform-browser-dynamic": "~7.2.0",
        "@angular/router": "~7.2.0",
        "core-js": "^2.5.4",
        "rxjs": "~6.3.3",
        "tslib": "^1.9.0",
        "zone.js": "~0.8.26",
        "document-register-element": "^1.7.2"
      },
      "devDependencies": {
        "@angular-devkit/build-angular": "~0.13.0",
        "@angular/cli": "~7.3.8",
        "@angular/compiler-cli": "~7.2.0",
        "@angular/language-service": "~7.2.0",
        "@types/jasmine": "~2.8.8",
        "@types/jasminewd2": "~2.0.3",
        "@types/node": "~8.9.4",
        "codelyzer": "~4.5.0",
        "concat": "^1.0.3",
        "fs-extra": "^8.1.0",
        "jasmine-core": "~2.99.1",
        "jasmine-spec-reporter": "~4.2.1",
        "karma": "~4.0.0",
        "karma-chrome-launcher": "~2.2.0",
        "karma-coverage-istanbul-reporter": "~2.0.1",
        "karma-jasmine": "~1.1.2",
        "karma-jasmine-html-reporter": "^0.2.2",
        "protractor": "~5.4.0",
        "ts-node": "~7.0.0",
        "tslint": "~5.11.0",
        "typescript": "~3.2.2"
      }
    }

我npm un build:elements按照指示使用构建，然后尝试以最简单的 html 进行托管

IE

<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <script src="analytics-counter.js"></script>
</head>

<body>
  <analytics-counter></analytics-counter>
</body>
</html>

最初我遇到了与这篇文章类似的错误（除了我提到custom-root的而不是“app-root”。

我已经从引导程序中删除了该组件，所以我现在在我的app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { Injector } from '@angular/core';
import { createCustomElement } from '@angular/elements';
import { AppComponent } from './app.component';
import { AnalyticsCounterComponent } from './analytics-counter/analytics-counter.component';

@NgModule({
  declarations: [
    AppComponent,
    AnalyticsCounterComponent
  ],
  imports: [
    BrowserModule
  ],
  entryComponents: [
    AnalyticsCounterComponent
  ],
  providers: []  
})
export class AppModule {
  constructor(private injector: Injector) {     
  }
  ngDoBootstrap() {    
    const el = createCustomElement(AnalyticsCounterComponent, { injector: this.injector });
    customElements.define('analytics-counter', el);
  }
}

我<custom-root>从 index.html 中删除了，并且看到了建议的 elswhere

我现在得到的错误是

Uncaught TypeError: Failed to construct 'HTMLElement': Please use the 'new' operator, this DOM object constructor cannot be called as a function.
        at t [as constructor] (analytics-counter.js:4)
        at new t (analytics-counter.js:4)
        at CustomElementRegistry.e.<computed> [as define] (analytics-counter.js:2)
        at new e (analytics-counter.js:4)
        at analytics-counter.js:4
        at Mo (analytics-counter.js:4)
        at analytics-counter.js:4
        at new e (analytics-counter.js:4)
        at Object.ti [as createNgModuleRef] (analytics-counter.js:4)
        at t.create (analytics-counter.js:4)

教程和解释看起来都非常简单，但我无法让最基本的示例正常工作。

这里有什么问题？

标签： angularangular-elements

解决方案

我能够重现您的错误。问题来自build-script.js. 您必须修改它并确保它只编译es2015.js文件而不是es5.js. ES5 在处理原生自定义元素时会遇到一些麻烦，因此您必须使用 ES2015。

所以它看起来像这样：

const files = [
  './dist/CustomElements/runtime-es2015.js',
  './dist/CustomElements/polyfills-es2015.js',
  './dist/CustomElements/main-es2015.js'
];

也可以随时查看我的 Angular Elements - Angular Custom Elements的工作演示存储库。输出已经在elements/文件夹中，所以你可以在index.html那里运行来测试它。通过在这个确切项目的构建脚本中将 es2015 替换为 es5，我能够重现该错误。

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