every
Example 1: Some values false
// RxJS v6+
import { every } from 'rxjs/operators';
import { of } from 'rxjs';
//emit 5 values
const source = of(1, 2, 3, 4, 5);
const example = source.pipe(
//is every value even?
every(val => val % 2 === 0)
);
//output: false
const subscribe = example.subscribe(val => console.log(val));
Example 2: All values true
// RxJS v6+
import { every } from 'rxjs/operators';
import { of } from 'rxjs';
//emit 5 values
const allEvens = of(2, 4, 6, 8, 10);
const example = allEvens.pipe(
//is every value even?
every(val => val % 2 === 0)
);
//output: true
const subscribe = example.subscribe(val => console.log(val));
Example 3: Values arriving over time and completing stream prematurely due to every returning false
// RxJS v6+
console.clear();
import { concat, of } from 'rxjs';
import { every, delay, tap } from 'rxjs/operators';
const log = console.log;
const returnCode = request => (Number.isInteger(request) ? 200 : 400);
const fakeRequest = request =>
of({ code: returnCode(request) }).pipe(
tap(_ => log(request)),
delay(1000)
);
const apiCalls$ = concat(
fakeRequest(1),
fakeRequest('invalid payload'),
fakeRequest(2) //this won't execute as every will return false for previous line
).pipe(
every(e => e.code === 200),
tap(e => log(`all request successful: ${e}`))
);
apiCalls$.subscribe();
Last modified 3yr ago