Angular 8 - Lazy loading modules : Error TS1323: Dynamic import is only supported when '--module' flag is 'commonjs' or 'esNext'

Question

When I updated Angular from 7 to Angular 8, getting error for lazy loading modules

I have tried the options, which are there in the angular upgradation guide

Made the below changes:

Before

    loadChildren: '../feature/path/sample- 
                         tage.module#SameTagModule'

After

   loadChildren: () => import('../feature/path/sample- 
                      tags.module').then(m => m.CreateLinksModule)

error TS1323: Dynamic import is only supported when '--module' flag is 'commonjs' or 'esNext'.

Answer 1

You are using dynamic import so you have to change your tsconfig.json like this to target your code to esnext module

{
  "compileOnSave": false,
  "compilerOptions": {
    "baseUrl": "./",
    "outDir": "./dist/out-tsc",
    "sourceMap": true,
    "declaration": false,
    "module": "esnext", // add this line
    "moduleResolution": "node",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "importHelpers": true,
    "target": "es2015",
    "typeRoots": [
      "node_modules/@types"
    ],
    "lib": [
      "es2018",
      "dom"
    ]
  }
}

Also make sure to check tsconfig.app.json dont have module and target config something like this

{
  "extends": "./tsconfig.json",
  "compilerOptions": {
    "outDir": "./out-tsc/app",
    "types": []
  },
  "include": [
    "src/**/*.ts"
  ],
  "exclude": [
    "src/test.ts",
    "src/**/*.spec.ts"
  ]
}

Answer 2

Just adding to @Tony's anwser, you might also need to do the same (change to "module": "esnext" ) in the tsconfig.app.json. In my case the tsconfig.json was already using esnext as the module but the tsconfig.app.json was still using es2015 and that caused this error.