underarm/lib/util.js

Transducers for JavaScript with Underscore API and Async extensions

'use strict'
// Based on Underscore.js 1.7.0
// http://underscorejs.org
//
// Which is distributed under MIT License:
// Underscore.js > (c) 2009-2014 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
// Underscore.js > Underscore may be freely distributed under the MIT license.

var util = require('./util-internal'),
    isFunction = util.isFunction,
    isArray = util.isArray,
    isString = util.isString,
    isNumber = util.isNumber,
    identity = util.identity

module.exports = function(_r){
  var _ = _r._ || {}
  _r._ = _
  _.iteratee = iteratee
  _.matches = matches
  _.property = property
}

function iteratee(value){
  var f
  if(isNull(value)){
    f = identity
  } else if(isFunction(value)){
    f = value
  } else if(isKey(value)){
    f = property(value)
  } else {
    f = matches(value)
  }
  return f
}

function property(key){
  return function(value){
    return value[key]
  }
}

function matches(attrs){
  var ps = pairs(attrs),
      len = ps.length
  return function(value){
    if(isNull(value)){
      return len === 0
    }
    var i = 0, p, k, v
    for(; i < len; i++){
      p = ps[i]
      k = p[0]
      v = p[1]
      if(v !== value[k] || !(k in value)){
        return false
      }
    }
    return true
  }
}

function isNull(value){
  return value === void 0 || value === null
}

function isKey(value){
  return isString(value) || isNumber(value)
}

function pairs(value){
  var key, ps = []
  for(key in value){
    if(value.hasOwnProperty(key)){
      ps.push([key, value[key]])
    }
  }
  return ps
}