munkacsitomi

const stringNumbers = ['123', '4.45', '5,25', 'abc', '10000'];
const numbers = stringNumbers.map(Number);

console.log(numbers); // [123, 4.45, NaN, NaN, 10000]


const stringBoolean = ['false', false, '0', 0, null, undefined];
const booleans = stringBoolean.map(Boolean);

console.log(booleans); // [true, false, true, false, false, false]

munkacsitomi

async send() {
  let success = false;
  try {
    const { data } = await httpPost();
    success = !data?.errors || data.errors.length === 0;
  } catch(e) {
    // handled below because failure can happen on two occasions
    // 1. httpPost fails
    // 2. the call was successful but the BE gives back error
    throw e;

munkacsitomi

// Compares 2 arrays of (primitive) values to see if they are the same
const doArraysMatch = (arr1, arr2) => arr1.length === arr2.length && arr1.every((element) => arr2.includes(element));

// Reusable function to combine arrays
const mergeArr = (...arr) => arr.reduce((acc, val) => [...acc, ...val], []);

// Group an array of objects by a specific key or property value
const movies = [
    { title: 'Test 1', year: 2020 },
    { title: 'Test 2', year: 2020 },

munkacsitomi

// Old, imperative way
const originalDoubleList = list => {
  const newList = [];
  for (let i = 0; i < list.length; i++) {
    newList[i] = list[i] * 2;
  }
  return newList;
};

console.log(originalDoubleList([20]));

munkacsitomi

function cached(fn) {
  // Create an object to store the results returned after each function execution.
  const cache = Object.create(null);

  // Returns the wrapped function
  return function cachedFn(str) {

    // If the cache is not hit, the function will be executed
    if (!cache[str]) {
        let result = fn(str);

munkacsitomi

const swapKeyVal = (obj) =>  Object.assign({}, ...Object.entries(obj).map(([a,b]) => ({ [b]: a })));

const getNumber = (num) => {
  const isStringType = typeof num === 'string';
  const isNumberType = typeof num === 'number';
  let hasNumber = false;
  let keyVal = { one: 1, two: 2, three: 3 };

  if (!isStringType && !isNumberType) {
    throw new Error('Unknown type');

munkacsitomi

# get all branches
git fetch
# undo any unplanned changes
git reset --hard
# revert last commit 
git reset --hard HEAD^
# reset to develop branch
git reset --hard origin/develop
# set the author name and email address to your commits
git config --global user.name "Your Name"

munkacsitomi

const tmp = [1, 2, 3, 1, 3, 4, 5];

const uniqueFirst = Array.from(new Set(tmp));
const uniqueSecond = tmp.filter((item, index) => tmp.indexOf(item) === index);
const uniqueThird = tmp.reduce((unique, item) => unique.includes(item) ? unique : [...unique, item], []);

const duplicatedValues = tmp.filter((item, index) => tmp.indexOf(item) !== index);

console.log(uniqueFirst);
console.log(uniqueSecond);

munkacsitomi

const ids = [100, 101, 102, 103];

// We can use reduce to wrap ids in an object
const first = ids.reduce((out, id) => {
    out.push({ id });
    return out;
}, []);

// Or use map to do the same
const second = ids.map((id) => {

munkacsitomi

const pause = (data, time) => new Promise(resolve => setTimeout(() => resolve(data), time));
const pauseReject = (data, time) =>
  new Promise((resolve, reject) =>
    setTimeout(() => reject(new Error(`Something went wrong in the ${data} promise`)), time)
  );

const parallelErrorHandlingWrong = () => {
  const firstPromise = pause('first', 3000);
  const secondPromise = pauseReject('second', 2000);
  const thirdPromise = pause('third', 1000);