koozdra

a = [ { name: 'bill', group: 'b' },
  { name: 'ann', group: 'a' },
  { name: 'ken', group: 'k' },
  { name: 'alex', group: 'a' } ]

_.reduce((sum, v) => {
  const { name, group } = v;
  const current = _.getOr([], [group, name])(sum);
  return _.set([group, name], [...current, v])(sum);
}, {})(a);

koozdra

shuffle_array = arr =>
  arr
    .map(a => [a, Math.random()])
    .sort(([, lr], [, rr]) => lr - rr)
    .map(([a]) => a);

user_action_for_state = (state, randy) => {
  if (state === 'p' || state === 'ps' || state === 'psa' || state === 'psam') {
    if (randy < 0.7) {
      return primary_action_names[state[state.length - 1]];

koozdra

shuffle_array = arr =>
  arr
    .map(a => [a, Math.random()])
    .sort(([, lr], [, rr]) => lr - rr)
    .map(([a]) => a);

koozdra

const times = require('lodash/fp/times');
const map = require('lodash/fp/map');
const sample = require('lodash/fp/sample');
const maxBy = require('lodash/fp/maxBy');
const find = require('lodash/fp/find');
const join = require('lodash/fp/join');
const flow = require('lodash/fp/flow');
const get = require('lodash/fp/get');
const sum = require('lodash/fp/sum');
const constant = require('lodash/fp/constant');

koozdra

const a = [
  { a: 'one', b: 4 },
  { a: 'two', b: 1 },
  { a: 'three', b: 4 },
  { a: 'four', b: 2 }
];

function argmaxAll(getterFunction, arr) {
  return reduce(
    ([max, arr], curr) => {

koozdra

_.reduce(
  ([numItemsSeen, mean], num) => [
    numItemsSeen + 1,
    mean + (num - mean) / (numItemsSeen + 1)
  ],
  [0, 0]
)([3, 4, 5, 6, 10, 100, 9]);

koozdra

const diceTriplets = sides =>
  _(sides)
    .range()
    .flatMap(a =>
      _(sides)
        .range()
        .flatMap(b =>
          _(sides)
            .range()
            .map(c => [a + 1, b + 1, c + 1])

koozdra

// modification version
function once(f) {
  let hasRun = false;
  let result;
  return () => {
    if (!hasRun) {
      result = f();
      hasRun = true;
    }
    return result;

koozdra

const _ = require('lodash');

function supersetInner(src) {
  if (src.length === 0) return [];

  const withouts = _.map(src, elem => superset(_.without(src, elem)));
  return [src, ..._.flatten(withouts)];
}

function superset(src) {

koozdra

const fs = require('fs');
const gm = require('gm');

function getSize(image) {
  return new Promise((resolve, reject) => {
    image.size((err, size) => {
      if (err) {
        reject(err);
        return;
      }