angular-cn/aio/content/examples/rx-library/src/operators.ts

import { Observable, of } from 'rxjs';

// #docregion

import { map } from 'rxjs/operators';

const nums = of(1, 2, 3);

const squareValues = map((val: number) => val * val);
const squaredNums = squareValues(nums);

squaredNums.subscribe(x => console.log(x));

// Logs
// 1
// 4
// 9

// #enddocregion