enti

A super light-weight key-value 'observable' wrapper that works with references.

usage

var Enti = require('enti');

var object = {
    foo: 'bar'
};

var model1 = new Enti(object);

model1.on('foo', function(foo){
    // object.foo changed. do something.
});

model1.set('foo', 'baz');

Enti knows about references too:

var model2 = new Enti(object);

model2.on('foo', function(foo){
    // object.foo changed. do something.
});

model1.set('foo', 'baz'); // sent into a different Enti, triggers events for all enti's

And you can use wildcards to watch for events:

Single level:

model1.on('*', function(value){
    // object.<anything> changed. do something.
    // value will be undefined, because the target path contains a wildcard.
});

model1.set('foo', 'baz');

Any level:

model1.on('**', function(value){
    // object.<anything>.<anything>.<anything>.<etc...> changed. do something.
    // value will be undefined, because the target path contains a wildcard.
});

model1.set('foo', 'baz');

Which can be combined with other keys:

model1.on('foo.*.bar', function(value){
    // object.foo.<anything>.bar changed. do something.
    // value will be undefined, because the target path contains a wildcard.
});

model1.set('foo', 'baz', {
    bar:1
});

And used with filters, to specify what data you are actually after:

model1.on('foo|*.bar', function(foo){
    // object.foo.<anything>.bar changed. do something.
    // model.get(left hand side of the pipe (|)) will be passed as the first parameter.
});

model1.set('foo', 'baz', {
    bar:1
});

All handlers will be passed an event object with the object the event was raised on, and the key and value that caused the event:

model1.on('something', function(value, event){
    event.key === 'something';
    event.value === value;
    event.target === model1.get('.');
});

API

.get(path)

returns the value on the attached object at path

You can get the currently attached object using '.'

 
model.get('.') // -> object
 

.set(path, value)

sets the value on the attached object at path to value

.remove(path)

deletes or splices the path on the attached object

.push([path,] value)

pushs the value into the attached object, or the array at path on the attached object.

push will throw if the target of the push is not an array.

.update([path,] value[, options])

updatess the target at path to match `value.

options can contain:

strategy: 'merge' (default) or 'morph'

merge: Merge value into target, retaining untouched keys in target morph: Merge value into target, removing any keys that are not in value

.move([path,] index)

moves the target at path to index

move will throw if the target of the move is not an array.

Paths

The path syntax is fairly minimal, with only 4 special tokens

. (dot/period)

Used to drill down into the object. eg:

var bar = get('foo.bar');

is equivilent to

var bar = object.foo.bar;

* (Wildcard)

Will match events from any key on the object

** (Feralcard)

Recursive wildecard. Will match events form any key, and any sub-key on the object.

| (Filter)

Functionally identical to a dot/period, but separates the target of an event from the rest of the path.

Given the below event listener:

model.on('foo|bar.baz', function(target){...})

If the model raises an event on foo.bar.baz, Enti will get('foo'), and pass the result to the handler.

Lazy initialisation

If you want to create an Enti to be attached to data later, you can pass false to the constructor:

var unattachedModel = new Enti(false);

This creates a model that will not listen to or be able to cause events to fire, meaning lower cycles for other Enti's that are attached.

You can check if a model is attached with the method .isAttached()