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type EventTarget<T> = EventTarget & T;

interface FormEvent<T> extends Event {
   target: EventTarget<T>;
}

function handleSubmit(event: FormEvent<{price: number}>) {
  event.target.price;  
}

joelbarbosa

progress bar exemples study https://jsbin.com/tufuyifazo/edit?html,console,output

joelbarbosa

const button = document.querySelector('button');
button.addEventListener("click", () => resizeWithTroattle(10));

const resizeWithTroattle = throttle(executeResize, 3000);
window.addEventListener("resize", () => resizeWithTroattle('test'));
function executeResize(number) {
  console.log("resize: " + number);
}

function throttle(fn, time) {

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const makeInterable = (array) => {
  let nextIndex = 0;
  
  return {
    next: () => {
      if (nextIndex < array.length) {
        return {value: array[nextIndex ++], done: false}
      } else {
        return {done: true};
     }

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const deepClone = obj => {
  const clone = {}
  for (let i in obj) {
    if (obj[i] != null && typeof obj[i] === 'object') {
      clone[i] = deepClone(obj[i])
    } else {
      clone[i] = obj[i]
    }
  }
  return clone

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const debounce = (fn, wait, immediate) => {
  let timeout;
  return () => {
    const later = () => {
      timeout = null;
      if (!immediate) fn.apply(this)
    }
    const callNow = immediate && !timeout;
    clearTimeout(timeout)
    timeout = setTimeout(later, wait)

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boucing loading animation https://jsbin.com/xevusopuza/edit?html,css,output

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// Return the total number of matching pairs of socks that John can sell.

// 9
// 10 20 20 10 10 30 50 10 20

// output
// 3

function sockMerchant(n, ar) {
    let totalPair=0;

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declare var __DEV__: boolean;

declare module 'react-native' {

  declare type Color = string | number;

  declare type Transform =
    { perspective: number } |
    { scale: number } |
    { scaleX: number } |

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// chunk
// Creates an array of elements split into groups the length of size.

const chunk = (input, size) => {
  return input.reduce((arr, item, idx) => {
    if (idx % size === 0) {
      return [...arr, [item]];
    } else {
      return [...arr.slice(0, -1), [...arr.slice(-1)[0], item]];
    }