从Angular 6迁移到Angular 7会导致错误-无法解决'core-js / es7 / reflect'

Question

Global Angular CLI: 7.3.8
Node v10.15.3
NPM 6.4.1
macos

我收到此错误 npm start

./node_modules/@angular-devkit/build-angular/src/angular-cli-files/models/jit-polyfills.js中的错误未找到模块：错误：无法解析“ core-js / es7 / reflect” '/ Users / XXX / projects / XXX / node_modules / @ angular-devkit / build-angular / src / angular-cli-files / models'..src / polyfills.ts中的错误找不到模块：错误：无法解决'/ Users / XXX / projects / XXX / src'中的'core-js / es7 / reflect'

Answer 1

为了解决此问题，我在tsconfig.json中将以下路径添加到了compilerOptions

{
  "compileOnSave": false,
  "compilerOptions": {
    "paths": {
      "core-js/es7/reflect": [
        "node_modules/core-js/proposals/reflect-metadata",
      ],
      "core-js/es6/*": ["node_modules/core-js/es"]
    },
    "baseUrl": "./",
    "outDir": "./dist/out-tsc",
    "sourceMap": true,
    "declaration": false,
    "moduleResolution": "node",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "target": "es5",
    "typeRoots": [
      "node_modules/@types"
    ],
    "lib": [
      "es2017",
      "dom"
    ]
  }
}

Answer 2

迁移到新的 Angular 版本后，“core-js/es6”或“core-js/es7”将不起作用。

您只需替换 import 'core-js/es/'

对于前。导入 'core-js/es6/symbol' 导入 'core-js/es/symbol'

这将正常工作。