Angular common error messages


Here is a list of frequent Angular issues. It’s not very long (yet), but it happens that I’m upgrading an Angular project and I see again issues that appear regularly when I change something in the configuration. If you have others to add you can send me a message.

  • Package '@angular/core' is not a dependency.

Maybe node_modules is missing tun npm i to install the packages and dependencies.

  • Your global Angular CLI version ([VERSION]) is greater than your local version ([VERSION]). The local Angular CLI version is used.

You should update the CLI version in your project. The global (-g) version is more up to date: npm install --save-dev @angular/cli@latest

  • 'ng' is not recognized as an internal or external command, operable program or batch file.

You should install Angular Cli: npm install -g @angular/cli. If you cannot install packages on your machine usually you can replace ng with npm start.

  • An unhandled exception occurred: Cannot find builder "@angular-devkit/build-angular:tslint

You are migrating from Angular 12 to Angular 13 and you are still using TSLint. TSLint has been deprecated and you shoud migrate to ESLint.

The steps involved:

  • add ESLint to your project: add @angular-eslint/schematics
  • migrate your lint configuration using ng g @angular-eslint/schematics:convert-tslint-to-eslint this uses a migration tool : It will install the following plugins: eslint-plugin-import, eslint-plugin-jsdoc, eslint-plugin-prefer-arrow and …
DELETE tslint.json 
CREATE .eslintrc.json (1084 bytes) 
UPDATE angular.json (3682 bytes) 
UPDATE package.json (1591 bytes) 

In your angular.json your lint configuration will be updated:

"lint": { 
    "builder": "@angular-eslint/builder:lint", 
      "options": { 
        "lintFilePatterns": [ 
  "defaultProject": "frontend", 
  "cli": { 
    "defaultCollection": "@angular-eslint/schematics" 

In this post I describe how to customize the ErrorHandler of Angular to customize the runtime errors: Angular Custom Error Handler

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