missing ponyfills when building an Angular solution using the symbol-observable library

[morsagmon]

Trying to build an Angular 13 Ionic 6 solution after a migration to capacitor 4 (from capacitor 3) and a full npm cleanup and re-installation, Getting:

Error: Cannot find module './ponyfill.js'
Require stack:
- C:\Users\morsa\Documents\IDrive-Sync\Dev Env\Projects\simplify-pilot\node_modules\symbol-observable\lib\index.js
- C:\Users\morsa\Documents\IDrive-Sync\Dev Env\Projects\simplify-pilot\node_modules\@angular\cli\lib\init.js
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:933:15)
    at Function.Module._load (node:internal/modules/cjs/loader:778:27)
    at Module.require (node:internal/modules/cjs/loader:1005:19)
    at require (node:internal/modules/cjs/helpers:102:18)
    at Object.<anonymous> (C:\Users\morsa\Documents\IDrive-Sync\Dev Env\Projects\simplify-pilot\node_modules\symbol-observable\lib\index.js:7:17)
    at Module._compile (node:internal/modules/cjs/loader:1101:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1153:10)
    at Module.load (node:internal/modules/cjs/loader:981:32)
    at Function.Module._load (node:internal/modules/cjs/loader:822:12)
    at Module.require (node:internal/modules/cjs/loader:1005:19) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [
    'C:\\Users\\morsa\\Documents\\IDrive-Sync\\Dev Env\\Projects\\simplify-pilot\\node_modules\\symbol-observable\\lib\\index.js',
    'C:\\Users\\morsa\\Documents\\IDrive-Sync\\Dev Env\\Projects\\simplify-pilot\\node_modules\\@angular\\cli\\lib\\init.js'
  ]
}
[ERROR] An error occurred while running subprocess ng.

        ng.cmd run app:build exited with exit code 1.

I guess this symbol-observable is used in rxjs (at least).

I tried manually installing:
npm i ponyfill

This did install ponyfill 0.0.1

However, still getting the above error.

Any pointers on how to solve are welcomed!

[sindresorhus]

Wrong repo