wrapup/lib/util.js

wraps up node packages for web development

"use strict";

var path    = require('path')
var fs      = require('fs')
var esprima = require('esprima')
var type    = require('prime/type')

var empty = function(object){
    for (var k in object) return false
    return true
}

var slice = Array.prototype.slice

var noop = function(){}

var throttle = function(fn){
    var timer
    return function(){
        var args = arguments
        clearTimeout(timer)
        timer = setTimeout(function(){
            fn.apply(null, args)
        }, 10)
    }
}

var relative = function(file){
    return path.relative(process.cwd(), file)
}

var relativeID = function(from, to){
    var file = path.relative(path.dirname(from), to)
    if (file[0] != '.') file = './' + file
    return (path.extname(file) == '.js') ? file.slice(0, -3) : file
}

var inPath = function(filepath, file){
    return path.relative(filepath, file).slice(0, 2) != '..'
}

var cache = {}
var getAST = function(name, dir){
    if (!dir) dir = __dirname + '/../includes'
    return function(callback){
        if (cache[name]) return callback(null, cache[name])
        fs.readFile(dir + '/' + name + '.js', 'utf-8', function(err, code){
            if (err) return callback(err)
            try { cache[name] = esprima.parse(code) }
            catch (e){ err = e }
            callback(err, cache[name])
        })
    }
}

var appendWalkerPath = function(path, key){
    return (path ? path + '.' : '') + key
}

var astWalker = function(ast, action){

    var walker = function(ast, parent, key, path){
        if (action(ast, parent, key, path)){
        } else if (Array.isArray(ast)){
            for (var i = 0; i < ast.length; i++) walker(ast[i], ast, i, appendWalkerPath(path, i))
        } else if (typeof ast == 'object'){
            for (var j in ast) walker(ast[j], ast, j, appendWalkerPath(path, j))
        }
    }

    walker(ast)
}

// thanks MooTools!
var cloneOf = function(item){
    switch (type(item)){
        case 'array'  : return cloneArray(item)
        case 'object' : return cloneObject(item)
        default       : return item
    }
}

var cloneObject = function(object){
    var clone = {}
    for (var key in object) clone[key] = cloneOf(object[key])
    return clone
}

var cloneArray = function(array){
    var i = array.length, clone = new Array(i)
    while (i--) clone[i] = cloneOf(array[i])
    return clone
}

var merge = function(object, key, value){
    if (typeof key == 'string'){
        if (type(object[key]) == 'object' && type(value[key]) == 'object'){
            merge(object[key], value)
        } else object[key] = value
    } else for (var i = 0; i < arguments.length; i++){
        var obj = arguments[i]
        for (var k in obj) merge(object, k, obj[k])
    }
    return object
}

var getFromPath = function(object, parts){
    if (typeof parts == 'string') parts = parts.split('.')
    for (var i = 0, l = parts.length; i < l; i++){
        if (object[parts[i]] != null) object = object[parts[i]]
        else return null
    }
    return object
}

exports.empty       = empty
exports.slice       = slice
exports.noop        = noop
exports.throttle    = throttle
exports.relative    = relative
exports.relativeID  = relativeID
exports.inPath      = inPath
exports.getAST      = getAST
exports.astWalker   = astWalker
exports.clone       = cloneOf
exports.merge       = merge
exports.getFromPath = getFromPath