Mutable value interface

npm install mutable
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Mutable value interface

Create mutable value wrapper, or extend existing object into one.

To be used by mutable interfaces, so they produce objects that share same characteristics.

Wrapper object keeps value at value property, and emits change events when value is changed.

var Mutable = require('mutable');
var obj = new Mutable();
var emitted;

obj.value = 'foo';
obj.on('change', function (value) { emitted = value; });
obj.value = 'bar';
console.log(emitted); // 'bar';

Additional utilities


Whether object is a mutable instance.

var isMutable = require('mutable/is');

console.log(isMutable({})); // false
console.log(isMutable(new Mutable())); // true


Create mutable out of two different values that may be mutable. If values are not mutable, boolean value is returned

var eq = require('mutable/eq');

console.log(isMutable(eq('foo', 'bar'))); // false
console.log(eq('foo', 'bar')); // false
console.log(eq('foo', 'foo')); // true

var m1 = new Mutable();

var em = eq(m1, 'foo');
console.log(isMutable(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 Mutable();
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



In your project path:

$ npm install mutable


You can easily bundle Mutable for browser with modules-webmake

Tests Build Status

$ npm test
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