how to use the pipe function from the rxjs library in typescript

index.ts
import { Observable } from 'rxjs';
import { map, filter } from 'rxjs/operators';

// create an Observable that emits numbers from 1 to 10
const numbers = Observable.range(1, 10);

// define a transformation function to be used in the pipeline
function square(n: number): number {
  return n * n;
}

// use the pipe() function to create a pipeline that first filters out even values, then squares each remaining value
const squaredOddNumbers = numbers.pipe(
  filter(n => n % 2 !== 0), // filter out even values
  map(square) // square each remaining value
);

// subscribe to the transformed Observable
squaredOddNumbers.subscribe(
  n => console.log(n), // logs 1, 9, 25, 49, 81
  err => console.error(err),
  () => console.log('done')
);
740 chars
24 lines