crocks/pointfree/reject.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) */

var curry = require('../core/curry')
var isArray = require('../core/isArray')
var isPredOrFunc = require('../core/isPredOrFunc')
var isFunction = require('../core/isFunction')
var isObject = require('../core/isObject')
var object = require('../core/object')
var predOrFunc = require('../core/predOrFunc')

var not =
  function (fn) { return function (x) { return !fn(x); }; }

// reject : Foldable f => (a -> Boolean) -> f a -> f a
function reject(pred, m) {
  if(!isPredOrFunc(pred)) {
    throw new TypeError(
      'reject: Pred or predicate function required for first argument'
    )
  }

  var fn =
    function (x) { return predOrFunc(pred, x); }

  if(m && isFunction(m.reject)) {
    return m.reject(fn)
  }

  if(isArray(m)) {
    return m.filter(not(fn))
  }

  if(isObject(m)) {
    return object.filter(not(fn), m)
  }

  throw new TypeError('reject: Foldable or Object required for second argument')
}

module.exports = curry(reject)