crocks/core/object.js

A collection of well known Algebraic Datatypes for your utter enjoyment.

/** @license ISC License (c) copyright 2017 original and current authors */
/** @author Ian Hofmann-Hicks (evil) */

function rejectUnit(obj) {
  return function(acc, key) {
    var value = obj[key]

    if(value !== undefined) {
      acc[key] = value
    }
    return acc
  }
}

function assign(x, m) {
  var result = Object.keys(m).reduce(rejectUnit(m), {})
  return Object.keys(x).reduce(rejectUnit(x), result)
}

function filter(f, m) {
  return Object.keys(m).reduce(function (acc, key) {
    if(f(m[key])) {
      acc[key] = m[key]
    }
    return acc
  }, {})
}

function map(f, m) {
  return Object.keys(m).reduce(function (acc, key) {
    acc[key] = f(m[key])
    return acc
  }, {})
}

function set(key, val, m) {
  var obj;

  return assign(( obj = {}, obj[key] = val, obj ), m)
}

function unset(key, m) {
  return Object.keys(m).reduce(function (acc, k) {
    if(m[k] !== undefined && k !== key) {
      acc[k] = m[k]
    }

    return acc
  }, {})
}

module.exports = {
  assign: assign, filter: filter,
  map: map, set: set, unset: unset
}