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Object representation of mutable value


var ObservableValue = require('observable-value');
var observable = new ObservableValue('foo');

Current value is accessible at value property:

observable.value; // 'foo' 

change events are emitted on any change

var emitted;
observable.on('change', function (event) { emitted = event; });
obj.value = 'bar';
console.log(emitted); // { newValue: 'bar', oldValue: 'foo' }; 


$ npm install observable-value

To port it to Browser or any other (non CJS) environment, use your favorite CJS bundler. No favorite yet? Try: Browserify, Webmake or Webpack

Additional utilities

isObservableValue (observable-value/is-observable-value)

Whether object shares ObservableValue interface

var isObservableValue = require('observable-value/is-observable-value');
console.log(isObservableValue({})); // false 
console.log(isObservableValue(new ObservableValue())); // true 


Create observable value out of two different values that may share ObservableValue but don't have to. If both values do not represent ObservableValue, plain boolean value is returned

var eq = require('observable-value/eq');
console.log(isObservableValue(eq('foo', 'bar'))); // false 
console.log(eq('foo', 'bar')); // false 
console.log(eq('foo', 'foo')); // true 
var m1 = new ObservableValue();
var em = eq(m1, 'foo');
console.log(isObservableValue(em)); // true 
console.log(em.value); // false 
em.on('change', function (value) { emitted = value; });
m1.value = 'foo';
console.log(emitted); // true 
console.log(em.value); // true 
m1.value = 'bar';
console.log(emitted); // false 
console.log(em.value); // false 
emitted = null;
m1.value = 'other';
console.log(emitted); // null 
console.log(em.value); // false 
var m2 = new ObservableValue();
m2.value = 'other';
em = eq(m1, m2);
console.log(em.value); // true 
m2.value = 'foo';
console.log(em.value); // false 
m1.value = 'foo';
console.log(em.value); // true 

Tests Build Status

$ npm test