A observable value representation
Latest commit a2c51a8 Aug 16, 2016 @Raynos committed on GitHub Merge pull request #15 from nick11roberts/master
Update license attribute.



build status NPM version Davis Dependency status

browser support


A observable value representation


var Observable = require("observ")

var v = Observable("initial value")
var stopListening = v(function onchange(newValue) {
  assert.equal(newValue, "new value")
v.set("new value")

var curr = v()
assert.equal(curr, "new value")

What about dominictarr/observable ?

Both observ & observable have the same interface of

  • thing() gets the value
  • thing.set(...) sets the value
  • thing(function (value) { ... }) listens to the value.

The way observ and observable differ is in listening.

  • observ will ONLY call the listener if .set() is invoked.
  • observable calls the listener IMMEDIATELY and calls it whenever .set() is invoked

observ can be used in a similar fashion to observable by using var watch = require("observ/watch"). You can then just watch(thing, function (value) { ... }) and it will call the listener immediately

Both observ & observable have a computed method with the same interface.

  • require("observable").compute
  • require("observ/computed")

Example computed

var Observable = require("observ")
var computed = require("observ/computed")

var one = Observable(1)
var two = Observable(2)

var together = computed([one, two], function (a, b) {
  return a + b

assert.equal(together(), 3)
assert.equal(together(), 7)


type Observable<A> :
  (() => A) &
  ((Function<A>) => void) & {
    set: (A) => void

observ : (A) => Observable<A>

observ/computed : (
  sources: Array<Observ<T>>,
  lambda: (...args: T) => S
) => Observ<S>


npm install observ


  • Raynos

MIT Licenced