callbag-drop-repeats

callbag-drop-repeats

Drops consecutive duplicate values. Works on either pullable or listenable sources. Takes an optional custom predicate function. If not provided then (a, b) => a === b will be used.

npm install callbag-drop-repeats

Examples

Listenables

const dropRepeats = require('callbag-drop-repeats');
const { forEach, map, interval, pipe, take } = require('callbag-basics');

pipe(
  interval(1000),
  take(3),
  map(() => 'Always me, but once'),
  dropRepeats(),
  forEach((x) => {
    console.log(x); // 'Always me, but once'
  })
);

Pullables

Without a predicate function:

const dropRepeats = require('callbag-drop-repeats');
const { forEach, fromIter, pipe } = require('callbag-basics');

pipe(
  fromIter([0, 0, 0, 1]),
  dropRepeats(),
  forEach((x) => {
    console.log(x); // 0
  })                // 1
);

With a predicate function:

const dropRepeats = require('callbag-drop-repeats');
const { forEach, fromIter, pipe } = require('callbag-basics');

pipe(
  fromIter([{ name: 'A' }, { name: 'A' }, { name: 'B' }]),
  dropRepeats((prev, curr) => prev.name === curr.name),
  forEach((x) => {
    console.log(x); // { name: 'A' }
  })                // { name: 'B' } 
);