Implement extention method w/ typescript.

typescript-extension.md

Implement extention method w/ typescript.

Array

// array.ext.ts

declare global {
  interface Array<T> {
    flatten(): Array<any>;
  }
}

Array.prototype.flatten = function (): Array<any> {
  return this.reduce((a, b) => a.concat(Array.isArray(b) ? b.flatten() : b), []);
};

Import array.ext.ts file at main.ts(Angular).

// main.ts

import { enableProdMode } from '@angular/core';
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';

import { AppModule } from './app/app.module';
import './app/utils/array.ext';

platformBrowserDynamic()
  .bootstrapModule(AppModule)
  .catch(err => console.error(err));

Reference

• https://kakkoyakakko2.hatenablog.com/entry/2018/06/12/003000