Properties

Overview

Properties can be used for some aspects of two-way-binding, like setting values of HTML inputs and setting attributes or styles to DOM elements, or bind them to data objects. They also integrate into the event dispatching mechanism by triggering events on the widget classes if property value changes, of course only if used on Events deriving objects.

import {Events} from 'events'
import {Property} from 'properties'

/**
 * Object defining a {Property} where we can listen on changes.
 */
class MyObject extends Events {

    constructor() {
        // Create property named 'some_prop'.
        new Property(this, 'some_prop');
    }

    /**
     * Default event handler if 'prop' gets changed on an
     * instance of ``MyObject``
     *
     * @param {Object} val - Value the property was set to.
     */
    on_some_prop(val) {
    }
}

// Create instance
let ob = new MyObject();

// When setting the value of 'some_prop', 'on_some_prop'
// default handler gets called
ob.some_prop = 'New Value';

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