尽管安装了模块，导入语句还是使 Angular 应用程序崩溃

Question

如果语法正确且库已经安装，import 语句会导致错误（附图）的原因是什么？ 可能是以下两个主要设置文件中的内容（package.json 和 tsconfig.json）？

我们继承了一个大型 Angular 应用程序，并使用 npm 在其中安装了 vega 和 vega-lite 和 vega-embed，现在我们正在尝试将 vega 图嵌入到所服务的本地服务器网页中。

主要文件内容如下：

package.json

{
  "name": "a-chis-angular",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "watch": "ng build --watch --configuration development",
    "test": "ng test"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "~12.2.0",
    "@angular/common": "~12.2.0",
    "@angular/compiler": "~12.2.0",
    "@angular/core": "~12.2.0",
    "@angular/forms": "~12.2.0",
    "@angular/platform-browser": "~12.2.0",
    "@angular/platform-browser-dynamic": "~12.2.0",
    "@angular/router": "~12.2.0",
    "bootstrap": "^5.1.0",
    "d3": "^7.0.0",
    "rxjs": "~6.6.0",
    "tslib": "^2.3.0",
    "vega": "^5.20.2",
    "vega-embed": "^6.18.2",
    "vega-lite": "^5.1.0",
    "zone.js": "~0.11.4"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~12.2.0",
    "@angular/cli": "~12.2.0",
    "@angular/compiler-cli": "~12.2.0",
    "@types/d3": "^7.0.0",
    "@types/jasmine": "~3.8.0",
    "@types/node": "^12.11.1",
    "jasmine-core": "~3.8.0",
    "karma": "~6.3.0",
    "karma-chrome-launcher": "~3.1.0",
    "karma-coverage": "~2.0.3",
    "karma-jasmine": "~4.0.0",
    "karma-jasmine-html-reporter": "~1.7.0",
    "typescript": "~4.3.5"
  }
}

tsconfig.json

{
  "compileOnSave": false,
  "compilerOptions": {
    "baseUrl": "./",
    "outDir": "./dist/out-tsc",
    "forceConsistentCasingInFileNames": true,
    "strictNullChecks": false,
    "strict": false,
    "noUnusedLocals": false,
    "noUnusedParameters": false,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "sourceMap": true,
    "declaration": false,
    "downlevelIteration": true,
    "experimentalDecorators": true,
    "moduleResolution": "node",
    "importHelpers": true,
    "target": "es2017",
    "module": "es2020",
    "lib": [
      "es2018",
      "dom"
    ]
  },
  "angularCompilerOptions": {
    "enableI18nLegacyMessageIdFormat": false,
    "suppressImplicitAnyIndexErrors": true,
    "strictInjectionParameters": true,
    "strictInputAccessModifiers": true,
    "strictTemplates": true,
    "noImplicitAny": false
  }
}

vega.component.html

<h3 class="center">Vega Viz</h3>

<figure id="vega" class="center"></figure>

vega.component.ts

import { Component, OnInit } from '@angular/core';
import embed from 'vega-embed';
import * as d3 from 'd3';

@Component({
  selector: 'app-vega',
  templateUrl: './vega.component.html',
  styleUrls: ['./vega.component.css']
})
export class VegaComponent implements OnInit {

  svg: any;

  margin = 50;
  width = 750 - (this.margin * 2);
  height = 400 - (this.margin * 2);

  constructor() { }

  ngOnInit(): void {
    this.createSvg();
    this.embedGraph();
  }

  createSvg(): void {
    this.svg = d3
      .select("figure#vega")
      .append("svg")
      .attr("width", this.width + (this.margin * 2))
      .attr("height", this.height + (this.margin * 2))
      .append("g")
      .attr("transform", "translate(" + this.margin + "," + this.margin + ")");
  }

  async embedGraph(): Promise<void> {
    const spec = "/assets/density-heatmaps.vg.json";
    embed.vegaEmbed("figure#vega", spec);
    const result = await embed("figure#vega", spec);
    console.log(result.view);
  }
}

我们已经尝试了以下所有方法：

import { default as vegaEmbed } from 'vega-embed';
import * as embed from 'vega-embed';
import embed from 'vega-embed';
var embed = require("vega-embed");
var vega = require('vega');
require('vega-embed');

它们都使应用程序崩溃。

Answer 1

我们通过将"esModuleInterop": true 和"allowSyntheticDefaultImports": true 添加到我们的tsconfig.json 文件中解决了相同的问题：。

现在完整的文件如下所示：

{
  "compileOnSave": false,
  "compilerOptions": {
    "baseUrl": "./",
    "outDir": "./dist/out-tsc",
    "esModuleInterop": true,
    "allowSyntheticDefaultImports": true,
    "forceConsistentCasingInFileNames": true,
    "strictNullChecks": false,
    "strict": false,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "sourceMap": true,
    "declaration": false,
    "downlevelIteration": true,
    "experimentalDecorators": true,
    "moduleResolution": "node",
    "importHelpers": true,
    "target": "es2017",
    "module": "es2020",
    "lib": [
      "es2018",
      "dom"
    ]
  },
  "angularCompilerOptions": {
    "enableI18nLegacyMessageIdFormat": false,
    "suppressImplicitAnyIndexErrors": true,
    "strictInjectionParameters": true,
    "strictInputAccessModifiers": true,
    "strictTemplates": true,
    "noImplicitAny": false
  }
}

This页面提示解决方法。