Howto: Setup Polyfills in Angular

Angular CLI based projects support polyfills. Here are the steps required to set them up on a newly created project which does not contain them so far:

1. Create src/polyfills.ts file (file name can be choosen freely)

2. Include the file in the tsconfig.app.ts and tsconfig.spec.ts configs, e.g.

   1{
   2    "compilerOptions": {
   3    },
   4    "files": [
   5        "src/polyfills.ts",
   6        "src/main.ts"
   7    ],
   8}
   

3. Make Angular include the file as a ployfill by adding it to the polyfills section in the angular.json file, e.g.

    1{
    2   "projects": {
    3       "architect": {
    4           "build": {
    5               "options": {
    6                   "polyfills": [
    7                       "src/polyfills.ts",
    8                       "zone.js"
    9                   ],
   10               }
   11           },
   12           "test": {
   13               "options": {
   14                   "polyfills": [
   15                       "src/polyfills.ts",
   16                       "zone.js",
   17                       "zone.js/testing"
   18                   ],
   19               }
   20           }
   21       }
   22   }
   23}
   

Those changes did the trick for me. Any code located in the polyfills.ts file was included in the transpiled code and added prior to any other application code.