underarm/lib/util-internal.js

Transducers for JavaScript with Underscore API and Async extensions

'use strict'
var toString = Object.prototype.toString,
    isArray = (Array.isArray || predicateToString('Array')),
    has = {}.hasOwnProperty

module.exports = {
  isArray: isArray,
  isFunction: isFunction,
  isNumber: predicateToString('Number'),
  isRegExp: predicateToString('RegExp'),
  isString: predicateToString('String'),
  isUndefined: isUndefined,
  identity: identity,
  arrayPush: arrayPush,
  stringAppend: stringAppend,
  objectMerge: objectMerge
}

function isFunction(value){
  return typeof value === 'function'
}

function isUndefined(value){
  return value === void 0
}

function predicateToString(type){
  var str = '[object '+type+']'
  return function(value){
    return toString.call(value) === str
  }
}

function identity(result){
  return result
}

function arrayPush(result, input){
  result.push(input)
  return result
}

function stringAppend(result, input){
  return result + input
}

function objectMerge(result, input){
  if(isArray(input) && input.length === 2){
    result[input[0]] = input[1]
  } else {
    var prop
    for(prop in input){
      if(has.call(input, prop)){
        result[prop] = input[prop]
      }
    }
  }
  return result
}