Source: alert.js

/**
 * A ALert component - <strike>UX/COE Compliant</strike><BR>
 * <BR><BR><img src=../images/alert.png width=100% style="border:1px lime dashed";>
 * <BR><BR><a href="../html/alert.html">DEMO</a>
 */
class Alert extends HTMLElement {
    constructor() {
        console.group("Alert.constructor")
	
        super();

        console.groupEnd();
    };
    
    /**
     * Set observable values here. When Changed, attributeChangedCallback is invoked
     * @observedAttributes
     */
    static get observedAttributes() {
        console.group("Alert.observedAttributes");

	this.observables = ["message"];
	console.log(this.observables);

        console.groupEnd();
        return this.observables;
    };

    /**
     * This function is called when this is attached to DOM
     * @connectedCallback. 
     */
    connectedCallback() {
        console.group("Alert.connectedCallback")
	
	let self = this;

	// FETCH ALL INTERESTING ELEMENTS
	this._fetchElements();

	// FETCH ALL ATTRIBUTES
	this._fetchAttributes();

	// REPLACE CONTENT IF NECESSARY WITH NEW STUFF
	this.innerHTML = `
		<wc-alert-inner>
		    <wc-alert-inner-lhs>
		        <wc-alert-icon>
			    <i class='fa fa-warning'></i><span>ALERT:</span>
		        </wc-alert-icon>

		        <wc-alert-message>
		            ${this.dom.content}
		        </wc-alert-message>
		    </wc-alert-inner-lhs>

		    <wc-alert-inner-rhs>
			<a href='#'>
		            CLOSE
			    <span class='closeit'><i class='fa fa-times'></i></span>
			</a>
		    </wc-alert-inner-rhs>
		</wc-alert-inner>`;

	let closer = this.querySelector("wc-alert-inner-rhs")

	closer.addEventListener("click", function() {
	    self._onClick();
	});

	if (this.classList.contains("thin")) {
	    let lhs = this.querySelector("wc-alert-inner-lhs");
	    let rhs = this.querySelector("wc-alert-inner-rhs");
	    lhs.style.marginLeft = "48px";
	    rhs.style.marginRight = "48px";
	}

	this._finalize();

	// SHOW IT NOW (NO FLICKERS) 
	this.style.visibility = "visible";

        console.groupEnd();
    };

    /**
     * Invoked When component is removed. Usually with a .remove() function call
     * @disconnectedCallback
     */
    disconnectedCallback() {
        console.group("Alert.disconnectedCallback")

	/* CLEAN UP NOW */

        console.groupEnd();
    };

    /**
     * Called with .setAttribute(...) function call
     * @attributeChangedCallback
     */
    attributeChangedCallback(attr, oldval, newval) {
        console.group("Alert.attributeChangedCallback:", attr, oldval, newval);

	this.properties = this.properties || [];

	// EXAMPLE ONLY. replace with observables
	switch(attr)
	{
	    case "message":
	    this.properties.message = newval;
	    this.querySelector("wc-alert-message").innerHTML = this.properties.message;
	    break;
	}
	
        console.groupEnd();
    };

    /**
     * Stores DOM elements of interest for future use
     * @_fetchElements
     */
    _fetchElements() {
	console.group("Alert._fetchElements");
	
	this.dom = this.dom || [];
	this.dom.content = this.innerHTML;

	console.groupEnd();
    };

    /**
     * Component attributes are _fetched and defaults are set if undefined
     * @_fetchAttributes
     * @param {string} [message=NOTSET] message text
     */
    _fetchAttributes() {
	console.group("Alert._fetchAttributes");
	
	this.properties = {
	    "cname"   : "Alert",
	    "author"  : "Mel Heravi",
	    "version" : "1.0",
	    "message" : "NOTSET"
	};
	
	// FETCH MESSAGE
	if (this.hasAttribute("message")) {
	    this.properties.message = this.getAttribute("message");
	    console.log("message: ", this.properties.message);
	}

	console.groupEnd();
    };

    /**
     * A sample callback usage function - see connectedCallback()
     * @_onClick
     */
    _onClick() {
	console.group("Button._onClick:", this.id);

	this.addEventListener("click", function() {
	    this.style.display = "none";
	});

	wc.publish(this, "wc-alert", {
	    id: this.id,
	    action: "closed"
	});

	console.groupEnd();
    };

    /**
     * Destroy the instance object and artifacts
     * @_destroy
     */
    destroy() {
	console.group("Alert.destroy:", this.id);

	// FREE POINTER
	delete this;

	// REMOVE ITEM FROM DOM
	this.parentNode.removeChild(this);

	console.groupEnd();
    };

    /**
     * SAVE DATA FOR ANALYTICS
     * @__finalize
     */
    _finalize() {
	console.group("Alert._finalize:", this.id);

	this.classList.add("wc");

	// ADD ANALYTICS HERE
	wc.getStats(this, this.properties.cname, this.properties.version);
	
	console.groupEnd();
    };

    /**
     * FOR TESTING PURPOSES
     * @test
     */
    static test() {
	console.group("Alert.test");

	console.log("testing results will be printed here...");

	console.groupEnd();
	return true;
    }
}

window.customElements.define('wc-alert', Alert);