角度4到角度5无法找到模块'@ angular / router'

Question

• I am upgrading from angular 2 to angular 5.
• after upgradation I am seeing the below errors in the the ts file.
• in angular5 do I need to remove @angular/core and @angular/router
• after upgradation providing the package.json also
• providing my error and code snippet below.
• can you tell me how to fix it.

error

[ts] Cannot find module '@angular/core'.
[ts] Cannot find module '@angular/router'.

code

import {Component, ElementRef, Input,Output,EventEmitter,Inject, OnInit,ViewChild} from '@angular/core';
import {KendoGridComponent} from '../grid/grid.component'
import { Router} from '@angular/router';

package.json

{
  "name": "SPORTS",
  "version": "1.0.0",
  "description": "SPORTS player - v0.2.37.1",
  "engines": {
    "node": "7.10.1"
  },
  "license": "ISC",
  "dependencies": {
    "@angular/animations": "^5.2.2",
    "@angular/common": "^5.2.2",
    "@angular/compiler": "^5.2.2",
    "@angular/compiler-cli": "^5.2.2",
    "@angular/core": "^5.2.2",
    "@angular/forms": "^5.2.2",
    "@angular/http": "^5.2.2",
    "@angular/platform-browser": "^5.2.2",
    "@angular/platform-browser-dynamic": "^5.2.2",
    "@angular/platform-server": "^5.2.2",
    "@angular/router": "^5.2.2",
    "@angular/upgrade": "2.0.0",
    "@ng-idle/core": "2.0.0-beta.2",
    "@ng-idle/keepalive": "2.0.0-beta.2",
    "@types/jquery": "^3.2.10",
    "@types/node": "^8.0.18",
    "@types/underscore": "^1.8.1",
    "@types/webpack": "^3.0.5",
    "angular2-in-memory-web-api": "0.0.21",
    "angular2-router-loader": "^0.3.5",
    "angular2-template-loader": "^0.6.2",
    "awesome-typescript-loader": "^3.2.1",
    "babel-minify-webpack-plugin": "0.2.0",
    "bootstrap": "^3.3.6",
    "commander": "^2.6.0",
    "compression-webpack-plugin": "1.0.1",
    "core-js": "^2.4.1",
    "css-loader": "^0.28.7",
    "del": "^3.0.0",
    "express": "^4.14.1",
    "extract-text-webpack-plugin": "^3.0.0",
    "file-loader": "^0.11.2",
    "file-saver": "^1.3.3",
    "html-webpack-plugin": "^2.30.1",
    "http-post": "^0.1.1",
    "http-proxy": "^1.8.1",
    "jquery": "2.2.3",
    "pako": "^1.0.5",
    "path": "^0.12.7",
    "raw-loader": "^0.5.1",
    "reflect-metadata": "^0.1.3",
    "require": "^2.4.20",
    "rxjs": "^5.5.6",
    "style-loader": "^0.18.2",
    "text-encoding-shim": "^1.0.0",
    "to-string-loader": "^1.1.5",
    "ts": "0.0.0",
    "typescript": "^2.4.2",
    "uglifyjs-webpack-plugin": "^0.4.6",
    "underscore": "^1.8.3",
    "webpack": "^3.5.6",
    "webpack-dev-server": "^2.7.1",
    "webpack-merge": "^4.1.0",
    "zone.js": "^0.6.23"
  },
  "devDependencies": {
    "gulp": "^3.9.1",
    "gulp-clean-css": "^3.8.0",
    "gulp-concat": "^2.6.1",
    "gulp-util": "^3.0.8",
    "jasmine-core": "~2.4.1",
    "jasmine-expect": "^3.0.1",
    "jasmine-jquery": "^2.1.1",
    "karma": "^1.2.0",
    "karma-chrome-launcher": "^0.2.3",
    "karma-cli": "^0.1.2",
    "karma-coverage": "^1.1.1",
    "karma-htmlfile-reporter": "^0.2.2",
    "karma-jasmine": "^0.3.8",
    "karma-jquery": "^0.1.0",
    "karma-sourcemap-loader": "^0.3.7",
    "karma-typescript": "^2.1.4",
    "karma-typescript-preprocessor": "^0.3.0"
  },
  "main": "server.js",
  "scripts": {
    "dev": "webpack-dev-server --config  ./webpack.dev.js --inline --progress --color ",
    "postinstall": "webpack -p --config ./webpack.prod.js --progress --profile --bail",
    "start": "node server.js"
  },
  "repository": {
    "type": "git",
    "url": "https://github.iSPORTS.com/player-Replatform/webcomponent.git"
  }
}

Answer 1

You need to install these dependencies manually.

$ npm i @angular/core -s
$ npm i @angular/router -s

I also faced the same issue while upgrading because of npm . I suggest you start using yarn instead.

Answer 2

1. Is this error coming from the compiler or an IDE tool like Intellisense? I find sometimes with installing/branch switching IDE tools like this can get confused and require a restart of the IDE.

2. If it won't compile, are the modules actually in your node_modules? If not, delete your package-lock.json or shrinkwrap.json and install again. NPM adds the package lock by default as of 5.0 and I find with complicated dependencies it can mess up sometimes.

3. If they are there, run npm prune and npm install again.

4. If that doesn't work, nuke node_modules alongside any lock file and install again.

5. Do any third-party libraries require an update? Angular 5 had some breaking API changes. Check their docs if that's the case.

6. Consider Yarn.

I'm pretty sure it's the first one, but I'll leave all the steps I usually take just for the sake of completion.

Answer 3

Make sure you are exporting RouterModule in each router module that has children. In the angular documentation this is not explicitly stated as being necessary -- it's merely included in the examples -- but it is necessary, as one finds out after the customary several hours of edit-run-sigh, edit-run-shout, edit-run-google-editWithHope-scream-considerSmashingKeyboard, edit-run-cry, edit-run-solveByAccident-feelMomentaryPride (repeat).

The upshot: include RouterModule . The meta upshot: pay attention to the little seemingly unnecessary code in official documentation.