xstream-drop-repeats-by-keys

pnpm install --save xstream-drop-repeats-by-keys

Like xstream dropRepeats, but acts on a stream of objects, and takes a list of keys as arguments. Those keys are the ones we want to check for equality.

description

An xstream operator to filter out duplicate objects judging by some keys.

Marble diagram:

Example:

import dropRepeatsByKeys from 'xstream-drop-repeats-by-keys'

const stream = xs.of({age: 27, name: 'Adele'}, {age: 28, name: 'Adele'})
  .compose(dropRepeatsByKeys(['name']))

stream.addListener({
  next: i => console.log(i),
  error: err => console.error(err),
  complete: () => console.log('completed')
})

> {age: 27, name: 'Adele'}
> completed

For debug purposes, you can also pass a boolean as the second argument, this will make the operator work in debug mode, so it will output to console.log what the difference in fields was when one of the fields determined by the keys is different. By default, the operator has this second argument set to false. See below:

import dropRepeatsByKeys from 'xstream-drop-repeats-by-keys'

const stream = xs.of({name: 'a'}, {name: 'b'}, {name: 'b'})
  .compose(dropRepeatsByKeys(['name'], true))

stream.addListener({
  next: i => console.log(i),
  error: err => console.error(err),
  complete: () => console.log('completed')
})

> {name: 'a'}
> xstream-drop-repeats-by-keys found different values for the key 'name': a !== b
> {name: 'b'}
> completed

License

MIT