twitter-entities.js

/*
 * twitter-entities.js
 * This function converts a tweet with "entity" metadata 
 * from plain text to linkified HTML.
 *
 * See the documentation here: http://dev.twitter.com/pages/tweet_entities
 * Basically, add ?include_entities=true to your timeline call
 *
 * Based off existing code from Wade Simmons
 * Licensed under the MIT license
 * http://wades.im/mons
 *
 * Requires jQuery
 * 
 */

function has_entities(entities) {
	if (!entities) return false;
	for (var entity in entities) {
		if (entity.length>0) return true;
	}
	return false;
};
function escapeHTML(text) {
	return $('<div/>').text(text).html();
};
function linkify_entities(tweet) {
	var index_map = {}, result="", last_i=0, i=0;

	// return w/o any processing if no entities passed
	if (!has_entities(entities)) {
		return escapeHTML(tweet);	
	}
	
	if (entities.urls) {
		$.each(entities.urls, function(i, entry) {
			index_map[entry.indices[0]] = [entry.indices[1], function(text) {
				return "<a href='" + escapeHTML(entry.url) + "' title='" + escapeHTML(entry.expanded_url) + "'>" + escapeHTML(entry.display_url) + "</a>";
			}];
		});
	}
	if (entities.media) {
		$.each(entities.media, function(i, entry) {
			index_map[entry.indices[0]] = [entry.indices[1], function(text) {
				return "<a href='" + escapeHTML(entry.url) + "' title='" + escapeHTML(entry.expanded_url) + "'>" + escapeHTML(entry.display_url) + "</a>";
			}];
		});
	}
	if (entities.hashtags) {
		$.each(entities.hashtags, function(i, entry) {
			index_map[entry.indices[0]] = [entry.indices[1], function(text) {
				return "<a href='http://twitter.com/search?q=" + escape("#" + entry.text) + "'>" + escapeHTML(text) + "</a>";
			}];
		});
	}
	if (entities.user_mentions) {
		$.each(entities.user_mentions, function(i, entry) {
			index_map[entry.indices[0]] = [entry.indices[1], function(text) {
				return "<a title='" + escapeHTML(entry.name) + "' href='http://twitter.com/" + escapeHTML(entry.screen_name) + "'>" + escapeHTML(text) + "</a>";
			}];
		});
	}
	// iterate through the string looking for matches in the index_map
	for (i = 0; i < tweet.length; i++) {
		var ind = index_map[i];
		if (ind) {
			var end = ind[0], func = ind[1];
			if (i > last_i) {
				result += escapeHTML(tweet.substring(last_i, i));
			}
			result += func(tweet.substring(i, end));
			i = end - 1;
			last_i = end;
		}
	}
	if (i > last_i) {
		result += escapeHTML(tweet.substring(last_i, i));
	}
	return result;
}