Link preview service for Angular.js

linkService.js

app.factory("$Link", function($q, $http){
	var LINKREGEX    = /(http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+ = &%@!\-\/]))?/g;
	var YOUTUBEREGEX = /(?:youtu\.be\/|youtube\.com\/(?:(?:watch)?\?(?:.*&)?v(?:i)?=|(?:embed|v|vi|user)\/))([^\?&\"'<> #]+)/;
	var IMAGEREGEX   = /(.+\w+\.(png|jpg|jpeg|ico|svg)$)/;
	var SERVICE      = "https://api.linkpreview.net";
	var KEY          = "<api-key>";
	var $Link        = {};

	/**
	 * Verifies if the provided text contains a link
	 * 
	 * @param  {String}  text The text to check for links
	 * @return {Boolean}      Whether the text has links
	 */
	$Link.isLink = function(text){
		var result = LINKREGEX.test(text);

		LINKREGEX.lastIndex = 0;

		return result;
	};

	/**
	 * Verifies if the provided text contains a youtube link
	 * 
	 * @param  {String}  text The text to check for youtube links
	 * @return {Boolean}      Whether the text has youtube links
	 */
	$Link.isYoutube = function(text){
		if(!this.isLink(text)){
			return false;
		}

		else{
			return YOUTUBEREGEX.test(text);
		}
	};

	/**
	 * Verifies if the provided text contains an image link
	 * 
	 * @param  {String}  text The text to check for an image link
	 * @return {Boolean}      Whether the text has image links
	 */
	$Link.isImage = function(text){
		if(!this.isLink(text)){
			return false;
		}

		else{
			return IMAGEREGEX.test(text);
		}
	};

	/**
	 * Gets the video id of the provided youtube link
	 * 
	 * @param  {String}      link The text youtube link
	 * @return {String|Null}      The id of the video, returns null if not found
	 */
	$Link.getYoutubeId = function(link){
		if(!this.isYoutube(link)){
			return null;
		}

		else{
			return YOUTUBEREGEX.exec(link)[1];
		}
	};

	/**
	 * Gets all the detected url links in a text
	 * 
	 * @param  {String} text The text where the links are contained
	 * @return {Array}       The list of links detected
	 */
	$Link.getLinks = function(text){
		var matches = [];

		var match;

		while((match = LINKREGEX.exec(text)) != null){
			matches.push(match[0]);
		}

		LINKREGEX.lastIndex = 0;

		return matches;
	};

	/**
	 * Parses all links in a text and returns a new text with formated links
	 * 
	 * @param  {String} text The text where the links are contained
	 * @return {String}      The new text with HTML formatted links
	 */
	$Link.parseLinks = function(text){
		if(!this.isLink(text)){
			return text;
		}

		else{
			return text.replace(LINKREGEX, function(match){
				var link = window.document.createElement("a");
				var text = window.document.createTextNode(match);

				link.href   = match;
				link.target = "_blank";

				link.appendChild(text);

				return link.outerHTML;
			});
		}
	};

	/**
	 * Requests the service for a link preview
	 * 
	 * @param  {String}  text The link text
	 * @return {Promise}      The result of the request
	 */
	$Link.getPreview = function(text){
		if(!this.isLink(text)){
			return $q.reject(new Error("Cannot preview from non-link text"));
		}

		else{
			var options = {
				params: {
					key: KEY,
					q: text
				}
			};

			return $http.get(SERVICE, options)
				.then(function(response){
					return response.data;
				});
		}
	};

	/**
	 * Creates an iframe tag with the embeded youtube video
	 * 
	 * @param  {String}      link The text where the youtube video is contained
	 * @return {String|Null}      The iframe where the youtuve video is embeded, returns null if not youtube link
	 */
	$Link.toYoutube = function(link){
		if(!this.isYoutube(link)){
			return null;
		}

		else{
			return "https://youtube.com/embed/" + this.getYoutubeId(link);
		}
	};

	/**
	 * Creates a img tag with the image
	 * 
	 * @param  {String}      link The text where the image link is contained
	 * @return {String|Null}      The img tag where the image is, returns null if not image link
	 */
	$Link.toImage = function(link){
		if(!this.isImage(link)){
			return null;
		}

		else{
			var img = window.document.createElement("img");

			img.src = link;

			return img.outerHTML;
		}
	};

	return $Link;
});