Source: video.js

/**
 * Video Component<BR>
 * <BR><BR><img src=/tk/lib/components/w/img/video.png width=40% style="border:1px lime dashed;padding:20px">
 * <BR><BR><a href="/tk/lib/components/w/html/video.html">DEMO</a>
 */
class Video extends HTMLElement {
    constructor() {
        wc.group("Video.constructor")

        super();

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

this.observables = []

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

    /**
     * This function is called when this is attached to DOM
     * @connectedCallback.
     */
    connectedCallback() {
        wc.group("Video.connectedCallback")

// GET PROPERTIES AND INTERESTING ELEMENTS
this._initialize();

// REPLACE CONTENT IF NECESSARY WITH NEW STUFF
this.innerHTML = `
   <video poster="${this.properties.poster}" ${this.properties.controls} ${this.properties.loop} ${this.properties.autoplay} style="background:${this.properties.background}" controlsList="${this.properties.download}">
       ${this.dom.content}
YOUR BROWSER DOES NOT SUPPORT THE VIDEO TAG
   </video>`

// ADD STATS AND OTHER FINAL STUFF
this._finalize();

        wc.groupEnd();
    };

    /**
       * @private
     * @_trasferAttr
     * @param {string} elem1
     * @param {string} elem2
     */
    _trasferAttr(elem1,elem2) {
wc.group("Video._trasferAttr:", elem1, elem2);

// TRANSFER
$.each($(elem1).prop("attributes"), function() {
   if (this.name != "id") { // DO NOT COPY ID
wc.log("copied:", this.name, this.value);

$(elem2).attr(this.name, this.value);
   }
});

wc.groupEnd();
    };

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

/** CLEAN UP NOW */

        wc.groupEnd();
    };

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

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

let obs = Video.observedAttributes;

for (let i = 0; i < obs.length; i++) {
   this.properties[obs[i]] = newval;
}

// YOUR CODE FOR CHANGES GO HERE (MAYBE NULL FIRST TIME THROUGH)
try {
   switch(attr)
   {
case "background":
this.style.background = 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("Video._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("Video._fetchAttributes");

this.properties = {
   cname        : "Video",
   author       : "Mel Heravi",
   id : "1561999105",
   version      : "1.0",
   controls     : "controls",
   poster       : "/tk/img/common/mel.cartoon.png",
   loop         : "false",
   autoplay     : "false",
   download     : "",
   background   : "#000",
   controlslist : "",
};

// 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]);
}

wc.log("ATTRIBUTES: ", this.properties);

wc.groupEnd();
    };

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

// FREE ALL MEMORY
// you should delete all created objects here

// FREE POINTER
delete this;

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

wc.groupEnd();
    };

    /**
     * configure the instance object and artifacts
     * @private
     * @_configure
     */
    configure(options) {
wc.group("Video.configure:", JSON.stringify(options));

// PROCESS ALL OPTIONS HERE

wc.groupEnd();
    };

    /**
     * SAVE DATA FOR ANALYTICS
     * @private
     * @_initialize
     */
    _initialize() {
wc.group("Video._initialize:", this.id);

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

// FETCH ALL ATTRIBUTES
this._fetchAttributes(this);

wc.groupEnd();
    };

    /**
     * SAVE DATA FOR ANALYTICS
     * @private
     * @_finalize
     */
    _finalize() {
wc.group("Video._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();
    };
}

window.customElements.define('wc-video', Video);