错误：无法解析“ \ node_modules \ @ angular-devkit \ build-angular \ src \ angular-cli-files \ models中的“ core-js / es7 / reflect”

Question

更新到Angular 7.3.6后，在ng serve上出现以下错误：

./node_modules/@angular-devkit/build-angular/src/angular-cli-files/models/jit-polyfills.js中的错误找不到模块：错误：无法解析“ core-js / es7 / reflect” '\ node_modules @ angular-devkit \ build-angular \ src \ angular-cli-files \ models'

这是我的package.json依赖项：

{
  "name": "frontend",
  "version": "0.0.0",
  "license": "MIT",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build --prod",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "^7.2.11",
    "@angular/cdk": "^7.3.6",
    "@angular/common": "^7.2.11",
    "@angular/compiler": "^7.2.11",
    "@angular/core": "^7.2.11",
    "@angular/flex-layout": "^7.0.0-beta.24",
    "@angular/forms": "^7.2.11",
    "@angular/http": "^7.2.11",
    "@angular/material": "^7.3.6",
    "@angular/platform-browser": "^7.2.11",
    "@angular/platform-browser-dynamic": "^7.2.11",
    "@angular/router": "^7.2.11",
    "adm-zip": "^0.4.13",
    "core-js": "^2.6.5",
    "hammerjs": "^2.0.8",
    "rxjs": "^6.4.0",
    "rxjs-compat": "^6.0.0-rc.0",
    "tslib": "^1.9.3",
    "zone.js": "^0.9.0"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "^0.13.7",
    "@angular/cli": "^7.3.7",
    "@angular/compiler-cli": "^7.2.11",
    "@angular/language-service": "^7.2.11",
    "@types/jasmine": "~3.3.12",
    "@types/jasminewd2": "~2.0.6",
    "@types/node": "~11.12.0",
    "codelyzer": "^5.0.0",
    "jasmine-core": "~3.3.0",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "^4.0.1",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "^2.0.5",
    "karma-jasmine": "~2.0.1",
    "karma-jasmine-html-reporter": "^1.4.0",
    "protractor": "^6.0.0",
    "ts-node": "~8.0.3",
    "tslint": "~5.14.0",
    "typescript": "3.1.6"
  }
}

Answer 1

您应该安装core-js@2.5.x包含此文件/模块的文件。请参阅预设环境文档。

Answer 2

如果您想使用3.0版，则可以在tsconfig.json文件中添加一个路径。

{
    "compilerOptions": {
        ...
        "paths": {
            "core-js/es7/reflect": [
                "node_modules/core-js/proposals/reflect-metadata"
            ]
        }
    }
}

注意：您需要检查node_modules/core-js/proposals/reflect-metadata相对路径，并在项目结构中根据需要对其进行更正。

Answer 3

core-js 3.0版具有一些重大更改：

https://github.com/zloirock/core-js/blob/master/docs/2019-03-19-core-js-3-babel-and-a-look-into-the-future.md

您应该在其中一个文件中找到与此行类似的行： import "core-js/es7/reflect";

更改为此： import "core-js/proposals/reflect-metadata";

Answer 4

对于Angular 8（来源）：

Angular CLI 8.0+直接管理所需的Angular polyfill，并且项目不需要直接依赖core-js（假设应用程序不手动包含其他core-js polyfills）。

我已解决：

• core-js从我的package.json依赖中删除
• 除去import 'core-js/es7/reflect';从我test.ts

Answer 5

就我而言，我只是改变了-->

import 'core-js/es6/reflect';
import 'core-js/es7/reflect';

到

import 'core-js/es/reflect';

它起作用了..

Answer 6

删除末尾的数字'es'删除路径'core-js/es/reflect'，就像对我来说也有用。

对于 EX：import 'core-js/es7/reflect';更改为import 'core-js/es/reflect';