The PlayCanvas Observer is a powerful JavaScript library for managing and observing changes to objects. It allows tracking modifications to nested properties, emitting events on changes, and maintaining state consistency. This is particularly useful in applications where state management and change tracking are critical, such as in data-driven interfaces or collaborative applications.

To install the NPM package, do:

npm install @playcanvas/observer --save-dev

import Observer from '@playcanvas/observer';

const data = {
    name: 'John',
    age: 30,
    address: {
        city: 'New York',
        zip: '10001'
    }
};

const observer = new Observer(data);

You can listen for changes to specific properties using the on method:

observer.on('address.city:set', (newValue, oldValue) => {
    console.log(`City changed from ${oldValue} to ${newValue}`);
});

observer.set('address.city', 'San Francisco'); // Logs: City changed from New York to San Francisco

To generate a UMD and ESM build of the Observer library, run:

npm install
npm run build

The UMD build is dist/index.js. The ESM build is dist/index.mjs.

To build the API reference manual, run:

npm run docs

A pre-built API reference manual is hosted here.