Source: pubsub.js

/**
 * Pubsub Component<BR>
 * <BR><BR><img src=/tk/lib/components/w/img/pubsub.png width=30% style="border:1px lime dashed;padding:20px">
 * <BR><BR><a href="/tk/lib/components/w/html/pubsub.html">DEMO</a>
 */
class Pubsub extends HTMLElement {
    constructor() {
        wc.group("Pubsub.constructor")
	
        super();
        wc.groupEnd();
    };
    
    /**
     * Set observable values here. When Changed, attributeChangedCallback is invoked
     * @observedAttributes
     */
    static get observedAttributes() {
        wc.group("Pubsub.observedAttributes");
	this.observables = [];
        wc.groupEnd();
        return this.observables;
    };
    /**
     * Called when this is attached to DOM
     * @connectedCallback. 
     */
    connectedCallback() {
        wc.group("Pubsub.connectedCallback")
	
	let self = this;
	tkloading.show();
	// ADD A RANDOM ID IF NONE EXIST
	if (!this.id) {
	    this.id = this.constructor.name.toLowerCase() + "-" + wc.uid();
	}
	// GET PROPERTIES AND INTERESTING ELEMENTS
	this._initialize();
	// ADD COMPONENT MARKTOP
	this.innerHTML = `<wc-include href='/tk/lib/components/misc/webpack/src/w/html/parts/pubsub/main.html'></wc-include>`;
	this._finalize();
	ga('send', {'hitType': 'event','eventCategory': 'wc-connected','eventAction': 'connected','eventLabel': this.properties.cname, 'eventValue':JSON.stringify({'env':wcENV,'app':wcAPP,'url':wcURL})});
        wc.groupEnd();
    };
    /**
     * Called with .setAttribute(...) function call
     * @attributeChangedCallback
     */
    attributeChangedCallback(attr, oldval, newval) {
        wc.group("Pubsub.attributeChangedCallback:", attr, oldval, newval);
	this.properties = this.properties || [];
	let obs = Pubsub.observedAttributes;
	for (let i = 0; i < obs.length; i++) {
	    if (newval) {
		this.properties[obs[i]] = newval;
	    }
	}
	
	// YOUR CODE FOR CHANGES GO HERE (MAYBE NULL FIRST TIME THROUGH)
	try {
	    switch(attr) 
	    {
		case "header":
		//this.querySelector("h1").innerHTML = newval;
		break;
		
		default:
		break;
	    }
	} catch(e) {
	    wc.warn(e.name + ' > ' + e.message);
	}
        wc.groupEnd();
    };
    /**
     * Stores DOM elements of interest for future use
     * @private
     * @_fetchElements
     */
    _fetchElements() {
	wc.group("Pubsub._fetchElements");
	
	this.dom = this.dom || [];
	this.dom.content = this.innerHTML;
	wc.groupEnd();
    };
    /**
     * Component attributes are _fetched and defaults are set if undefined
     * @private
     * @_fetchAttributes
     */
    _fetchAttributes() {
	wc.group("Pubsub._fetchAttributes");
	
	this.properties = {
	    uparam	: "",
	    cname	: "Pubsub",
	    author	: "Mel M. Heravi, Ph.D.",
	    version	: "1.0"
	};
	
	// SAVE WIDGET SPECIFIC PROPERTIES
	this.propertiesW = [];
	
	// SAVE ALL OTHER PROPERTIES
	let attrs = wc.getAttributes(this)
	
 	for (var key in attrs) {
	    let attr = this.getAttribute(key) || this.properties.key;
	    this.properties[key]  = this.getAttribute(key);
	    this.propertiesW[key] = this.getAttribute(key);
	    wc.log(key + ": " + attrs[key]);
	}
	// SET ALL INITIAL ATTRIBUTES
 	for (var key in this.properties) {
	    switch(key) 
	    {
		case "header":
		break;
		
		default:
		break;
	    }
	}
	wc.log("ATTRIBUTES: ", this.properties);
	wc.groupEnd();
    };
    /**
     * configure the instance object and artifacts
     * @configure
     * @param {string} data use data if exist else use 'this.properties.cfg' parameter
     */
    configure(data) {
	wc.group("Pubsub.configure:", data);
	// IF JSON VARIABLE (data) IS PROVIDED
	if (data) {
	    this._process(data);
	} else {
	    let self = this;
	    $.getJSON(this.properties.cfg, function(data) {
		self._process(data);
	    }).fail(function(jqXHR, textStatus, errorThrown) {
		alert("ERROR: INCOMING TEXT " + jqXHR.responseText);
	    });
	}
	wc.groupEnd();
    };
    /**
     * _process the instance object and artifacts
     * @private
     * @_process
     */
    _process(data) {
	wc.group("Pubsub._process:", data);
	
	// DO WHATEVER WITH THE DATA
	
	wc.groupEnd();
    };
    /**
     * Initialize component
     * @private
     * @_initialize
     */
    _initialize() {
	wc.group("Pubsub._initialize:", this.id);
	// FETCH ALL INTERESTING ELEMENTS
	this._fetchElements();
	// FETCH ALL ATTRIBUTES
	this._fetchAttributes();
	
	wc.groupEnd();
    };
    /**
     * Save data for analytics and final wrap up
     * @private
     * @_finalize
     */
    _finalize() {
	wc.group("Pubsub._finalize:", this.id);
	this.classList.add("wc");
	// ADD ANALYTICS HERE
	wc.setStats(this, this.properties.cname, this.properties.version);
	
	// SHOW IT NOW (NO FLICKERS) 
	this.style.visibility = "visible";
	wc.groupEnd();
    };
    /**
     * Invoked When component is removed. Usually with a .remove() function call
     * @disconnectedCallback
     */
    disconnectedCallback() {
        wc.group("Pubsub.disconnectedCallback")
	ga('send', {'hitType': 'event','eventCategory': 'wc-disconnected','eventAction': 'disconnected','eventLabel': this.properties.cname, 'eventValue':JSON.stringify({'env':wcENV,'app':wcAPP,'url':wcURL})});
        wc.groupEnd();
    };
    /**
     * Destroy the instance object and artifacts
     * @destroy
     */
    destroy() {
	wc.group("Pubsub.destroy");
	// FREE ALL MEMORY
	// you should delete all created objects here
	
	// FREE POINTER
	delete this;
	
	// REMOVE ITEM FROM DOM
	this.parentNode.removeChild(this);
	ga('send', {'hitType': 'event','eventCategory': 'wc-destroyed','eventAction': 'distroy','eventLabel': this.properties.cname, 'eventValue':JSON.stringify({'env':wcENV,'app':wcAPP,'url':wcURL})});
	wc.groupEnd();
    };
}
window.customElements.define('wc-pubsub', Pubsub);