shawn-dsz

const searchTree = (fn) => (obj) =>
  Array.isArray(obj)
    ? obj.length == 0
      ? null
      : searchTree(fn)(obj[0]) || searchTree(fn)(obj.slice(1))
    : fn(
        obj,
        () => searchTree(fn)(obj.children || []),
        () => obj
      );

shawn-dsz

const barr = [
  { id: 1, is: true },
  [
    { id: 2, is: false },
    [
      { id: 3, is: true },
      { id: 4, is: false },
    ],
  ],
];

shawn-dsz

const foo = [1, [2, [3, 4]]];

// foo.flat(Infinity)
function flatten(a) {
  return a.reduce((flat, i) => {
    if (Array.isArray(i)) {
      return flat.concat(flatten(i));
    }
    return flat.concat(i);
  }, []);

shawn-dsz

const maccs = [
  {
    name: 'cheese burger',
    type: [
      { name: 'fries', types: [{ name: 'chilli' }, { name: 'chicken salt' }] },
      { name: 'bacon', types: [{ name: 'crispy' }, { name: 'bbq' }] },
      { name: 'sauce', types: [{ name: 'ranch' }, { name: 'soy' }] },
    ],
  },
  {

shawn-dsz

// https://crocoder.dev/blog/map-filter-reduce-exercises/

const input = [1, -4, 12, 0, -3, 29, -150];

input.filter((a) => a > 0).reduce((a, b) => a + b, 0);

const input2 = [12, 46, 32, 64];
const sorted = input2.sort((a, b) => a - b);

const res = sorted.reduce(

shawn-dsz

var memo = {};
const fib = (n) => {
  if (n <= 1) return 1;
  if (memo[n]) return memo[n];
  memo[n] = fib(n - 1) + fib(n - 2)
  return memo[n];
};

fib(1);
fib(2);

shawn-dsz

const names = ['a', 'b', 'bd', 'bc', 'f'];

const b = names.sort((a, b) => {
  if (a < b) return -1;
  if (b < a) return 1;
  return 0;
});
b;

shawn-dsz

const files: MyFile[] = [
  { name: 'raz', size: 45, age: 4 },
  { name: 'pop', size: 33, age: 6 },
  { name: 'foo', size: 10, age: 9 },
  { name: 'crackle', size: 21, age: 2 },
  { name: 'baz', size: 22, age: 8 },
  { name: 'bar', size: 15, age: 11 },
];

interface MyFile {

shawn-dsz

const assert = (v) => {
  if (!v) {
    throw new Error('False');
  }
  return true;
};

const groupBy = (arr, fn) =>
  arr
    .map(typeof fn === 'function' ? fn : (val) => val[fn])

shawn-dsz

/**
 * Code recipe: Writing JavaScript groupBy() function
 */

// https://sebhastian.com/javascript-group-by/

const movies = [
  { title: 'Sonic the Hedgehog', year: 2020 },
  { title: 'Mulan', year: 2020 },
  { title: 'Godzilla vs. Kong', year: 2021 },