referential
v0.5.25
Published
Mutable state container for sharing data safely in a functional or reactive programming style.
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Readme
referential
Refer to mutable state safely.
Referential makes it easy to share mutable state safely. A Ref
to an object
or subtree always refers to the same underlying data regardless how it's
mutated.
Heavily optimized for reads.
Motivating example
var state = {a: {b: {c: "world"}}}
var render = (function() {
var template = state.a.b.c;
return function() {
return "Hello " + template
}
}())
state.a.b.c = "This will be lost on you."
console.log(render()) // Hello world
Install
$ npm install referential --save
Usage
refer = require('referential')
// Create a reference
ref = refer({a: 1})
// Get underlying value of reference
ref() // {a: 1}
ref('a') // 1
// Mutate state
ref.set('b', 2) // {a: 1, b: 2}
ref.set({c: 3}) // {a: 1, b: 2, c: 3}
// Extend state
ref.extend({c: {d: 1, e: 2}}) // {a: 1, b: 2, c: {d: 1, e: 2}}
ref.extend({c: {d: 3}}) // {a: 1, b: 2, c: {d: 3, e: 2}}
// Create entire tree as needed
ref.set('d.e.f', 4) // {a: 1, b: 2, c: 3, d: {e: {f: 4}}}
// Get reference to subtree
ref2 = ref.refer('d.e')
ref2() // {f: 4}
// Mutate subtree (and update parent)
ref2.set('g', 5)
ref2() // {f: 4, g: 5}
// Mutate parent (and update subtree)
ref.set('d.e.f', 6)
ref() // {a: 1, b: 2, c: 3, d: {e: {f: 6, g: 5}}}
ref2() // {f: 6, g: 5}
// Clone ref, create new tree
ref3 = ref2.clone()
ref3.set('g', 6)
ref3() // {f: 6, g: 6}
ref2() // {f: 6, g: 5}
// Bind to update event, should print `x was set to 2 from 1`
ref4 = refer({x: 1})
ref4.on('set', function(name, newValue, oldValue) {
console.log(name + ' was set to ' + newValue + ' from ' + oldValue)
})
ref4.set('x', 2)
Check the tests for more examples.