Swap Font Awesome Icons based on the number of likes post receives. Can be used with my WordPress Like System.

alternate-function

<?php
/**
 * Swap Function (5) with the following
 * (5)(b) Front end button
 */
function getPostLikeLink( $post_id ) {
        $theme_object = wp_get_theme();
        $themename = esc_attr( $theme_object->Name ); // the theme name
		$like_count = get_post_meta( $post_id, "_post_like_count", true ); // get post likes
		if ( ( !$like_count ) || ( $like_count && $like_count == 0 ) ) { // no votes, set up empty variable
				$likes = 'Like';
				$icon = '<i class="fa fa-heart"></i>'; // no likes, icon is heart
		} elseif ( $like_count && $like_count != 0 ) { 
			$likes = esc_attr( $like_count );
			if ( $like_count <= 19 ) {
				$icon = '<i class="fa fa-star-o"></i>'; // 1-19 likes, icon is empty star
			} elseif ( $like_count <= 29 ) {
				$icon = '<i class="fa fa-star-half-empty"></i>'; // 20-29 likes, icon is half-full star
			} elseif ( $like_count <= 49 ) {
				$icon = '<i class="fa fa-star"></i>'; // 30-49 likes, icon is full star
			} elseif ( $like_count > 49 ) {
				$icon = '<i class="fa fa-rocket"></i>'; // 50 or more likes, icon is rocket ship
			}
		}
		$output = '<span class="post-like">';
		$output .= '<a href="#" data-post_id="'.$post_id.'">';
		if ( AlreadyLiked( $post_id ) ) { // already liked, set up unlike addon
				$output .= '<span class="unliker"><i class="fa fa-times-circle"></i></span><span class="like prevliked">'.$icon.'</i></span>';
				$output .= ' <span class="count alreadyliked">'.$likes.'</span></a></span>&nbsp; ';
		} else { // normal like button
				$output .= '<span class="unliker"></span><span class="like">'.$icon.'</span>';
				$output .= ' <span class="count">'.$likes.'</span></a></span>&nbsp; ';
		}
		return $output;
}

post-like

jQuery(document).ready(function() {

	jQuery(".post-like a").click(function(){
	
		heart = jQuery(this);
		post_id = heart.data("post_id");
		
		jQuery.ajax({
			type: "post",
			url: ajax_var.url,
			data: "action=post-like&nonce="+ajax_var.nonce+"&post_like=&post_id="+post_id,
			success: function(count){
				if( count.indexOf( "already" ) !== -1 )
				{
					var lecount = count.replace("already","");
					if (lecount==0)
					{
						var lecount = "Like";
						var icon = "<i class='fa fa-heart'></i>";
					}
					else if (lecount<=19)
					{
						var icon = "<i class='fa fa-star-o'></i>";
					}
					else if (lecount<=29)
					{
						var icon = "<i class='fa fa-star-half-empty'></i>";
					}
					else if (lecount<=49)
					{
						var icon = "<i class='fa fa-star'></i>";
					}
					else if (lecount>49)
					{
						var icon = "<i class='fa fa-rocket'></i>";
					}
					heart.children(".like").removeClass("pastliked").addClass("disliked").html(icon);
					heart.children(".unliker").text("");
					heart.children(".count").removeClass("liked").addClass("disliked").text(lecount);
				}
				else
				{
					if (count==0)
					{
						var icon = "<i class='fa fa-heart'></i>";
					}
					else if (count<=19)
					{
						var icon = "<i class='fa fa-star-o'></i>";
					}
					else if (count<=29)
					{
						var icon = "<i class='fa fa-star-half-empty'></i>";
					}
					else if (count<=49)
					{
						var icon = "<i class='fa fa-star'></i>";
					}
					else if (count>49)
					{
						var icon = "<i class='fa fa-rocket'></i>";
					}
					heart.children(".like").addClass("pastliked").removeClass("disliked").html(icon);
					heart.children(".unliker").html("<i class='fa fa-times-circle'></i>");
					heart.children(".count").addClass("liked").removeClass("disliked").text(count);
				}
			}
		});
		
		return false;
	})
	
})

Thanks for the great plugin. You rockzzz...