standard pagination pattern for node

pagination.js

extend = require(extend);

/*	Creates an array of items representing the pagination navigation.
	You can then pass this to your template engine eg handlebars 
	Also see the PHP version:
	https://gist.github.com/robmint/e4b037aba1687195524c

 	Based on the work of Jason Coleman
	http://www.strangerstudios.com/blog/2006/07/paginate-your-site-like-digg/ 
*/


var Pagination = function (c) {

	config = {
		totalitems: 0,
		page: 1,
		adjacents: 1, 
		limit: 15,
		page: 1,
		targetpage: "/",
		pagestring: "p="
	}
	this.config = extend(config, c);


    for (var key in this.config) {
    	this[key] = this.config[key];
    	console.log(key);
	}

	console.dir(this.config);

	//other vars
	prev = page - 1;									//previous page is page - 1
	next = page + 1;									//next page is page + 1
	lastpage = Math.ceil(totalitems / limit);				//lastpage is = total items / items per page, rounded up.
	lpm1 = lastpage - 1;								//last page minus 1
	
	pages = [];

	if(lastpage > 1)
	{	

		//previous button
		if (page > 1) 
			pages.push({previous: true, url: targetpage + pagestring + prev});
		
		//pages	
		if (lastpage < 7 + (adjacents * 2))	//not enough pages to bother breaking it up
		{	
			for (counter = 1; counter <= lastpage; counter++)
			{
				if (counter == page)
					pages.push({selected: true, label: counter});
				else
					pages.push({label: counter, url: targetpage + pagestring + counter});
			}
		}
		else if(lastpage >= 7 + (adjacents * 2))	//enough pages to hide some
		{
			//close to beginning; only hide later pages
			if(page < 1 + (adjacents * 3))		
			{
				for (counter = 1; counter < 4 + (adjacents * 2); counter++)
				{
					if (counter == page)
						pages.push({selected: true, label: counter});
					else
						pages.push({label: counter, url: targetpage + pagestring + counter});
					}
				pages.push({ellipsis: true});	
				pages.push({label: lpm1, url:  targetpage + pagestring + lpm1});
				pages.push({label: lastpage, url:  targetpage + pagestring + lastpage});
			}
			//in middle; hide some front and some back
			else if(lastpage - (adjacents * 2) > page && page > (adjacents * 2))
			{
				pages.push({label: '1', url: targetpage + pagestring + "1"});
				pages.push({label: '2', url: targetpage + pagestring + "2"});
				pages.push({ellipsis: true});	

				for (counter = page - adjacents; counter <= page + adjacents; counter++)
				{
					if (counter == page)
						pages.push({selected: true, label: counter});
					else
						pages.push({label: counter, url: targetpage + pagestring + counter});
				}
				pages.push({ellipsis: true});	
				pages.push({label: lpm1, url:  targetpage + pagestring + lpm1});
				pages.push({label: lastpage, url:  targetpage + pagestring + lastpage});
			}
			//close to end; only hide early pages
			else
			{
				pages.push({label: '1', url: targetpage + pagestring + "1"});
				pages.push({label: '2', url: targetpage + pagestring + "2"});
				pages.push({ellipsis: true});	
				for (counter = lastpage - (1 + (adjacents * 3)); counter <= lastpage; counter++)
				{
					if (counter == page)
						pages.push({selected: true, label: counter});
					else
						pages.push({label: counter, url: targetpage + pagestring + counter});
				}
			}
		}
		
		//next button
		if (page < counter - 1) 
			pages.push({next: true, url: targetpage + pagestring + next});
	}
	this.pages = pages;
}

module.exports = Pagination;

/* Typical Handlebars template 

{{#each pages}}
    {{#if previous}}
        <li class="first"><a href="{{url}}" title="Previous"><span
                class="glyphicons glyphicons-circle-arrow-left"></span></a></li>
    {{else}}
        {{#if selected}}
            <li class="active"><a href="{{url}}">{{label}}</a></li>
        {{else}}
            {{#if ellipsis}}
                <li><a class="disabled glyph-sm"><span
                        class="glyphicons glyphicons-more"></span></a></li>
            {{else}}
                {{#if next}}
                    <li class="last"><a href="{{url}}" title="Next"><span
                            class="glyphicons glyphicons-circle-arrow-right"></span></a></li>
                {{else}}
                    <li><a href="{{url}}">{{label}}</a></li>
                {{/if}}
            {{/if}}
        {{/if}}
    {{/if}}
{{/each}}

*/