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A observable value representation


A observable value representation

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

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")
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>

npm install observ

  • Raynos