node-submerge
Recursively merge various objects into a single new object, optionally capable of reflecting changes on the merged object
Install
npm install --save submerge
As of version 1.1.0 Submerge (mostly its dependencies) requires NodeJS 4 or higher. If you are 'stuck' on NodeJS 0.10 - 0.12, you will need to specify the version (the latest is 1.0.9).
$ npm install --save submerge@^1.0.9
Usage
There are three ways of creating merged objects, all of which are based on the 'first come, first serve'-principle, the first key encountered will be on the merged object. There is one exception, nested object, if a key holds an object and it can inherit one or more properties from another object, it will.
submerge(object A, object B, ...)
This creates a merged object which contains all keys/values encountered in all provided objects. The merged object is fully enumarable and mutable, but changes will only affect the merged object itself
submerge.locked(object A, object B, ...)
This creates a merged object which contains all keys/values encountered in all provided objects. The merged object is enumerable but will have [Getter/Setter] at all keys, any change to existing keys will not be honered. New keys, however, cannot (yet) be prevented.
submerge.live(object A, object B, ...)
This creates a merged object which contains all keys/values encountered in all provided objects. The merged object is enumerable but will have [Getter/Setter] at all keys, any change to existing keys will not only be honered but also persisted in the originating object.
Events
When using the submerge.live method, you may want to know which variables are being changed, this can be done using the event mechanism (which is only available for live merges).
change
Live submerged objects have the change event, this was designed to work from the object returned by submerge.live(...).
var submerge = require('submerge'),
live = submerge.live({a:'this is a'}, {b:'this is b'});
live.on('change', function(key, newValue, oldValue) {
console.log('live changed key', key, 'new', newValue, 'was', oldValue);
});
live.a = 'still a, but different';Do note that as the change handler was designed to be used on the object returned by submerge.live the key will actually use the object dot notation for nested keys, e.g. live.my.object.value will have the key 'my.object.value' in the change-event.
License
GPLv2 © Konfirm
