f-utility/lib/random-take.js

functional utilities

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.allot = exports.grab = exports.pick = exports.take = undefined;

var _katsuCurry = require("katsu-curry");

var _randomFloor = require("./random-floor");

var _iterate = require("./iterate");

function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }

var keys = Object.keys;

/**
 * Take values randomly from objects or arrays
 * @function random.take
 * @param {boolean} encase - do we want to return the unwrapped value?
 * @param {mixed} input - an array or object
 * @return {mixed} either random values from the object.values or the array values, possibly wrapped
 * @public
 * @example
 * import {random} from 'f-utility'
 * const {take} = random
 * const a2e = `abcde`.split(``)
 * const a2eObject = {a: 1, b: 2, c: 3}
 * take(true, a2e) // [`a`]
 * take(true, a2e) // [`d`]
 * take(false, a2e) // `c`
 * take(false, a2e) // `b`
 * take(true, a2eObject) // {b: 2}
 * take(true, a2eObject) // {c: 3}
 * take(false, a2eObject) // 1
 * take(false, a2eObject) // 3
 */

var take = exports.take = (0, _katsuCurry.curry)(function (encase, o) {
  // ducktype: array-like with something in it
  if (o && o[0] && o.length) {
    var found = (0, _randomFloor.floor)(o.length);
    var selection = o[found];
    return !encase ? selection : [selection];
  }
  // for objects
  var ks = keys(o);
  var index = (0, _randomFloor.floor)(ks.length);
  var key = ks[index];
  var value = o[key];
  if (encase) return _defineProperty({}, key, value);
  return value;
});

/**
 * partially-applied take - pull values randomly from an array or an object
 * @function random.pick
 * @param {Array|Object} x - something to take values from
 * @public
 * @example
 * import {random} from 'f-utility'
 * const {pick} = random
 * pick(`abcde`.split(``)) // `a`
 * pick(`abcde`.split(``)) // `d`
 * pick(`abcde`.split(``)) // `b`
 */
var pick = exports.pick = take(false);

/**
 * partially-applied take - pull values randomly from an array or an object
 * @function random.grab
 * @param {Array|Object} x - something to take values from
 * @public
 * @example
 * import {random} from 'f-utility'
 * const {pick} = random
 * pick(`abcde`.split(``)) // [`a`]
 * pick(`abcde`.split(``)) // [`d`]
 * pick(`abcde`.split(``)) // [`b`]
 */
var grab = exports.grab = take(true);

/**
 * pull some number of values from an array or object
 * @function random.allot
 * @param {number} howMany - how many values to take
 * @param {mixed} ofThing - array or object
 * @return {Array} values
 * @public
 * @example
 * import {random} from 'f-utility'
 * const {allot} = random
 * const a2e = `abcde`.split(``)
 * allot(3, a2e) // [`d`, `b`, `c`]
 * allot(3, a2e) // [`a`, `e`, `c`]
 * allot(3, a2e) // [`e`, `b`, `a`]
 * const a2eObject = {a: 1, b: 2, c: 3, d: 4, e: 5}
 * allot(3, a2eObject) // {d: 4, e: 5, a: 1}
 * allot(3, a2eObject) // {a: 1, c: 3, a: 1}
 */
var allot = exports.allot = (0, _katsuCurry.curry)(function (howMany, ofThing) {
  return (0, _iterate.iterate)(howMany, function () {
    return pick(ofThing);
  });
});