Fixi

API

import * as fixi from 'fixi'

fixi.fix

Create the stream or property fix point for a function. For s = fix(f), the stream s will satisfy s = f(s).

For example

let s = fixi.fix((stream) => {
  return stream
    .delay(10)
    .take(4)
    .toProperty(() => null)
})
let values = runStream(s)
assert.equal(values, [null, null, null, null])

One can iterativley compute the fixed point by setting

let s1 = f(K.never())
let s2 = f(s1)
// ...

The fix point will then be the limit of this sequence. (It will, in fact, be the least fix point.)

Decoupling

The function f must return a stream that is decoupled from the input stream. For example, the function

let f = (stream) => {
  return stream
    .map((x) => x + 1)
    .toProperty(() => 0)
}

does not have a fix point.

However, one can delay a stream

let s = fixi.fix((stream) => {
  return stream
    .delay()
    .map((x) => x + 1)
    .toProperty(() => 0)
})

This will produce the sequence 0, 1, 2, ... and emit one value on every tick.

fix.ev

let n = ho('div', {click: ev(() => 'hey')})
n.stream.onValue((x) => {
  console.log('clicked element', x)
})