extend-observable.md

extendObservable

Quite similar to Object.assign, extendObservable takes two or more arguments, a target object and one or more properties maps. It adds all key-value pairs from the properties to the target as observable properties.

If an argumentless function is passed as value of a property, extendObservable will introduce a computed property instead of an observable property.

var Person = function(firstName, lastName) {
	// initialize observable properties on a new instance
	extendObservable(this, {
		firstName: firstName,
		lastName: lastName
	});
}

var matthew = new Person("Matthew", "Henry");

// add a observable property to an already observable object
extendObservable(matthew, {
	age: 353
});

(N.b: observable(object) is actually an alias for extendObservable(object, object))