@artezio/observable

Typescript library helps you to observe models changes. Library is written with es7 decorators. The decorator listens for any changes in the observable object thanks to the proxy and generates an event.

Installation

Using npm:

$ npm install @artezio/observable

Using yarn:

$ yarn add @artezio/observable

Example

Use observable decorator to make all instances observable. To understand that changes have been made we compare old value with new, so to catch changes in complex types like array you should mark array property with "observableProperty" decorator.

import { observable, observableProperty, getObservable } from 'artezio/observable';

@observable
class Person {
    name: string;
    @observableProperty
    pets: string[];
    constructor(name: string, pets?: string[]) {
        this.name = name;
        this.pets = pets || [];
    }

    addPet(pet: string) {
        this.pets.push(pet);
    }
}

const person = new Person('Name');
const observableMethods = getObservable(person);
observableMethods && observableMethods.subscribe(person => {
    console.log('updated Person:', person);
})
person.addPet('Cat');/// will log "updated Person: Person {name: "Name", pets: Array(1)}"

API

To make you object observable simply run this:

import { toObservable } from 'artezio/observable';
var myObject = {...};
myObject = toObservable(myObject);

Now your object is observable and you can subscribe on its changes, to do it you should get method subscribe:

import { getObservable } from 'artezio/observable';
getObservable(myObject).subscribe(obj => {
    console.log("My object has changed, now it:", obj);
})

NOTICE! getObservable() returns object with methods OR undefined. If you are not sure that object is observable, check the result:

const observableMethods = getObservable(someObject);
if(observableMethods) {
    observableMethods.subscribe(...)
}

There is another way to check out if the object is observable, by using the isObservable function. It will be explained later

To fire event immediately do following:

getObservable(myObject).emitChange();

You can also both mute() and unmute() your observable object:

getObservable(myObject).mute();
myObject.name = 'newName';// will not generate an event;
getObservable(myObject).unmute();
myObject.name = 'oldName';// will log "My object has changed, now it: {name: oldName}"

To find out if the object is observable use isObservable():

import { isObservable } from 'artezio/observable';
console.log(isObservable(myObject));// true;

To make all instances of particular Class mark it with observable decorator

import { observable } from 'artezio/observable';

@observable
class MyClass {
    ...
}

To understand that changes have been made we compare old value with new, so to catch changes in complex types like array you should mark array property with "observableProperty" decorator.

import { observable, observableProperty } from 'artezio/observable';

@observable
class MyClass {
    @observableProperty
    myProperty: object;
    ...
}