selectn/selectn.js

Curried property accessor function that resolves deeply-nested object properties via dot/bracket-notation string path while mitigating TypeErrors via friendly and composable API.

!function(e){if("object"==typeof exports&&"undefined"!=typeof module)module.exports=e();else if("function"==typeof define&&define.amd)define([],e);else{var f;"undefined"!=typeof window?f=window:"undefined"!=typeof global?f=global:"undefined"!=typeof self&&(f=self),f.selectn=e()}}(function(){var define,module,exports;return (function e(t,n,r){function s(o,u){if(!n[o]){if(!t[o]){var a=typeof require=="function"&&require;if(!u&&a)return a(o,!0);if(i)return i(o,!0);var f=new Error("Cannot find module '"+o+"'");throw f.code="MODULE_NOT_FOUND",f}var l=n[o]={exports:{}};t[o][0].call(l.exports,function(e){var n=t[o][1][e];return s(n?n:e)},l,l.exports,e,t,n,r)}return n[o].exports}var i=typeof require=="function"&&require;for(var o=0;o<r.length;o++)s(r[o]);return s})({1:[function(require,module,exports){
'use strict'

const curry2 = require('curry2')
const dotted = require('brackets2dots')
const splits = require('dotsplit.js')
const string = Object.prototype.toString

module.exports = curry2(selectn)

/**
 * Curried property accessor function that resolves deeply-nested object properties via dot/bracket-notation
 * string path while mitigating `TypeErrors` via friendly and composable API.
 *
 * @param {String|Array} path
 * Dot/bracket-notation string path or array.
 *
 * @param {Object} object
 * Object to access.
 *
 * @return {Function|*|undefined}
 * (1) returns `selectn/1` when partially applied.
 * (2) returns value at path if path exists.
 * (3) returns undefined if path does not exist.
 */
function selectn (path, object) {
  let idx = -1
  const seg = string.call(path) === '[object Array]' ? path : splits(dotted(path))
  const end = seg.length
  let ref = end ? object : undefined

  while (++idx < end) {
    if (Object(ref) !== ref) return undefined
    ref = ref[seg[idx]]
  }

  return typeof ref === 'function' ? ref() : ref
}

},{"brackets2dots":2,"curry2":3,"dotsplit.js":4}],2:[function(require,module,exports){
'use strict';

/*!
 * exports.
 */

module.exports = brackets2dots;

/*!
 * regexp patterns.
 */

var REPLACE_BRACKETS = /\[([^\[\]]+)\]/g;
var LFT_RT_TRIM_DOTS = /^[.]*|[.]*$/g;

/**
 * Convert string with bracket notation to dot property notation.
 *
 * ### Examples:
 *
 *      brackets2dots('group[0].section.a.seat[3]')
 *      //=> 'group.0.section.a.seat.3'
 *
 *      brackets2dots('[0].section.a.seat[3]')
 *      //=> '0.section.a.seat.3'
 *
 *      brackets2dots('people[*].age')
 *      //=> 'people.*.age'
 *
 * @param  {String} string
 * original string
 *
 * @return {String}
 * dot/bracket-notation string
 */

function brackets2dots(string) {
  return ({}).toString.call(string) == '[object String]'
       ? string.replace(REPLACE_BRACKETS, '.$1').replace(LFT_RT_TRIM_DOTS, '')
       : ''
}

},{}],3:[function(require,module,exports){
'use strict'

/*!
 * imports.
 */

var bind = Function.prototype.bind || require('fast-bind')

/*!
 * exports.
 */

module.exports = curry2

/**
 * Curry a binary function.
 *
 * @param {Function} fn
 * Binary function to curry.
 *
 * @param {Object} [self]
 * Function `this` context.
 *
 * @return {Function|*}
 * If partially applied, return unary function, otherwise, return result of full application.
 */

function curry2 (fn, self) {
  var out = function () {
    if (arguments.length === 0) return out

    return arguments.length > 1
      ? fn.apply(self, arguments)
      : bind.call(fn, self, arguments[0])
  }

  out.uncurry = function uncurry () {
    return fn
  }

  return out
}

},{"fast-bind":5}],4:[function(require,module,exports){
'use strict'

var toString = Object.prototype.toString

/**
 * Transform dot-delimited strings to array of strings.
 *
 * @param  {String} string
 * Dot-delimited string.
 *
 * @return {Array}
 * Array of strings.
 */

function dotsplit (string) {
  var idx = -1
  var str = compact(normalize(string).split('.'))
  var end = str.length
  var out = []

  while (++idx < end) {
    out.push(todots(str[idx]))
  }

  return out
}

/**
 * Replace escapes with a placeholder.
 *
 * @param  {String} string
 * Dot-delimited string.
 *
 * @return {String}
 * Dot-delimited string with placeholders in place of escapes.
 */

function normalize (string) {
  return (toString.call(string) === '[object String]' ? string : '').replace(/\\\./g, '\uffff')
}

/**
 * Drop empty values from array.
 *
 * @param  {Array} array
 * Array of strings.
 *
 * @return {Array}
 * Array of strings (empty values dropped).
 */

function compact (arr) {
  var idx = -1
  var end = arr.length
  var out = []

  while (++idx < end) {
    if (arr[idx]) out.push(arr[idx])
  }

  return out
}

/**
 * Change placeholder to dots.
 *
 * @param  {String} string
 * Dot-delimited string with placeholders.
 *
 * @return {String}
 * Dot-delimited string without placeholders.
 */

function todots (string) {
  return string.replace(/\uffff/g, '.')
}

/*!
 * exports.
 */

module.exports = dotsplit

},{}],5:[function(require,module,exports){
'use strict';
module.exports = function(boundThis) {
  var f = this
    , ret

  if (arguments.length < 2)
    ret = function() {
      if (this instanceof ret) {
        var ret_ = f.apply(this, arguments)
        return Object(ret_) === ret_
          ? ret_
          : this
      }
      else
        return f.apply(boundThis, arguments)
    }
  else {
    var boundArgs = new Array(arguments.length - 1)
    for (var i = 1; i < arguments.length; i++)
      boundArgs[i - 1] = arguments[i]

    ret = function() {
      var boundLen = boundArgs.length
        , args = new Array(boundLen + arguments.length)
        , i
      for (i = 0; i < boundLen; i++)
        args[i] = boundArgs[i]
      for (i = 0; i < arguments.length; i++)
        args[boundLen + i] = arguments[i]

      if (this instanceof ret) {
        var ret_ = f.apply(this, args)
        return Object(ret_) === ret_
          ? ret_
          : this
      }
      else
        return f.apply(boundThis, args)
    }
  }

  ret.prototype = f.prototype
  return ret
}

},{}]},{},[1])(1)
});