Pagination plugin & Query plugin, sitting in a tree...

lawnchair-paginated-query.js

/*
    Confused? Start here: http://brian.io/lawnchair/

    This plugin takes two awesome other plugins and mashes their naughty bits together.
    Queries are awesome. Pagination is awesome. Paginated Queries are awesome^2.

    I take no credit for any of the heavy lifting done here, all I did was take two genius
    things and smash them together.
*/

// - NOT jsonPath or jsonQuery which are horrendously complex and fugly
// - simple query syntax 'its just javascript'
// - simple string interpolation
// - search then sorting
Lawnchair.plugin((function(){
    //
    var interpolate = function(template, args) {
        var parts = template.split('?').filter(function(i) { return i != ''})
        ,   query = ''

        for (var i = 0, l = parts.length; i < l; i++) {
            query += parts[i] + args[i]
        }
        return query
    }

    var sorter = function(p) {
        return function(a, b) {
            if (a[p] < b[p]) return -1
            if (a[p] > b[p]) return 1
            return 0
        }
    }
    //
    return {
        // query the storage obj
        where: function() {
            // ever notice we do this sort thing lots?
            var args = [].slice.call(arguments)
            ,   tmpl = args.shift()
            ,   last = args[args.length - 1]
            ,   qs   = tmpl.match(/\?/g)
            ,   q    = qs && qs.length > 0 ? interpolate(tmpl, args.slice(0, qs.length)) : tmpl
            ,   is   = new Function(this.record, 'return !!(' + q + ')')
            ,   r    = []
            ,   cb
            // iterate the entire collection
            // TODO should we allow for chained where() to filter __results? (I'm thinking no b/c creates funny behvaiors w/ callbacks)
            this.all(function(all){
                for (var i = 0, l = all.length; i < l; i++) {
                    if (is(all[i])) r.push(all[i])
                }
            })
            // overwrite working results
            this.__results = r
            // callback / chain
            if (args.length === 1) this.fn(this.name, last).call(this, this.__results)
            return this
        },

	    // FIXME should be able to call without this.__results
        // ascending sort the working storage obj on a property (or nested property)
        asc: function(property, callback) {
            this.fn(this.name, callback).call(this, this.__results.sort(sorter(property)))
            return this
        },

        // descending sort on working storage object on a property
        desc: function(property, callback) {
            this.fn(this.name, callback).call(this, this.__results.sort(sorter(property)).reverse())
            return this
        },

        //mash in the page method from the pagination plugin
        page: function (page, callback) {
            // some defaults
            var objs  = []
            ,   count = 20 // TODO make this configurable
            ,   cur   = ~~page || 1
            ,   next  = cur + 1
            ,   prev  = cur - 1
            ,   start = cur == 1 ? 0 : prev*count
            ,   end   = start >= count ? start+count : count

            // grab all the records
            // FIXME if this was core we could use this.__results for faster queries
            objs = this.__results

            // grab the metadata
            var max  = Math.ceil(objs.length/count)
            ,   page = { max: max
                       , next: next > max ? max : next
                       , prev: prev == 0 ? 1 : prev
                       }

            // reassign to the working resultset
            this.__results = page[this.name] = objs.slice(start, end)

            // callback / chain
            if (callback) this.fn('page', callback).call(this, page)
            return this
        }
    }
/////
})())