friendlyanon

// Ideally, Map would have this as a method, but the proposal is still only on
// stage 2: https://github.com/tc39/proposal-upsert
function emplace<K, V>(
  map: Map<K, V>,
  key: K,
  supplier: (key: K) => V,
): V;
function emplace<K, V, This>(
  map: Map<K, V>,
  key: K,

friendlyanon

export type AtLeastOne<T> = [T, ...T[]];

export function groupByUsing<V, K extends keyof V, U>(
    iterable: Iterable<V>,
    key: K | ((value: V, index: number) => V[K]),
    callback: (value: V, index: number) => U,
): Map<V[K], AtLeastOne<U>> {
  const mapper = typeof key !== "function" ? (v: V) => v[key] : key;
  const map = new Map<V[K], AtLeastOne<U>>();

friendlyanon

/**
 * Explode implementation. The inputs to this function are not validated, use
 * {@link explode} for inputs that might not meet the requirements.
 *
 * @param delimiter Non-empty string
 * @param string
 * @param limit Integer in the range of [2 - 4294967295]
 */
export function explodeUnchecked(
  delimiter: string,

friendlyanon

function drop(iterator, amount) {
  for (let i = 0; !(i >= amount); ++i) {
    if (iterator.next().done) {
      break;
    }
  }

  return iterator;
}

friendlyanon

function once(fn) {
  const { name, length } = fn;
  let called = false;

  // match .name of argument
  const wrapped = {
    [name]() {
      if (!called) {
        called = true;
        fn.apply(this, arguments);

friendlyanon

export const groupByUsing = (iterable, key, callback) => {
  const mapper = typeof key !== "function" ? x => x[key] : key;
  const map = new Map();

  let i = -1;
  for (const value of iterable) {
    const mappedKey = mapper(value, ++i, key);
    const mappedValue = callback(value, i, key);

    const group = map.get(mappedKey);

friendlyanon

async function concurrentWorker(context, callback) {
  const { queue } = context;
  const abortToken = Symbol();
  while (context.ok) {
    const { done, value } = queue.next();
    if (done) {
      context.ok = false;
      return;
    }

friendlyanon

export const IndexableMap = class extends Map {
  constructor(iterable) {
    super();
    this._values = [];
    if (iterable != null) {
      for (const [key, value] of iterable) {
        this.set(key, value);
      }
    }
  }

friendlyanon

function* parseNdjson(ndjson) {
  let i = 0;
  do {
    const newline = ndjson.indexOf("\n", i);
    const string = newline === -1 ? ndjson.slice(i) : ndjson.slice(i, newline);
    const json = string.trim();
    if (json) {
      yield JSON.parse(json);
    }
    i = newline + 1;

friendlyanon

const map = {
  "-1": "💥",
  "0": "🟦",
};

const inRange = (number, max) => 0 <= number && number < max;

const neighbors = [
  [-1, -1], [-1, 0], [-1, 1],
  [0,  -1],          [ 0, 1],