paulfranco

Interview Questions

Node.js

Q1: What do you mean by Asynchronous API? ☆☆

Answer: All APIs of Node.js library are aynchronous that is non-blocking. It essentially means a Node.js based server never waits for a API to return data. Server moves to next API after calling it and a notification mechanism of Events of Node.js helps server to get response from the previous API call.

Source: tutorialspoint.com

boxgames1

const EventEmitter = require("events").EventEmitter;

class Pizza extends EventEmitter {
  constructor(size = 1) {
    super();
    this.ovenTime = this._ovenTime(size);
    this.maxIngredients = this._maxIngredients(size);
    this.ingredients = [];
    this.timeToReleasePizza = 5;
  }

mjackson

import { useRef, useState } from 'react'

function useUndo([state, setState]) {
  const history = useRef([state])
  const [index, setIndex] = useState(0)

  function undo() {
    setIndex(Math.max(index - 1, 0))
  }
  function redo() {

mjackson

// We want to subscribe to some data. Here are 2 ways to do the SAME thing.

// 1. setup some state
// 2. subscribing to a uid, set posts when they come in
// 3. unsubscribing when the component unmounts
// 4. when the uid changes:
//   - unsubscribing from prev uid
//   - re-subscribing to the new uid

// Here's a render prop:

mjackson

import { useEffect, useRef } from 'react';

function getItem(storage, key) {
  const value = storage.getItem(key);

  if (!value) return null;

  try {
    return JSON.parse(value);
  } catch (error) {

dmitriy-novikov

import * as actions from 'action-creators';

// Тип, который берет action-creators, выводит типы всех экшенов по отдельности и собирает их в union
type InferValueTypes<T> = T extends { [key: string]: infer U }
    ? U
    : never;
  
  type ActionTypes = ReturnType<InferValueTypes<typeof actions>>;

simonrelet

import React from 'react'

/**
 * @typedef {object} State The state of asynchronous hooks.
 * @property {object | null} error The error.
 * @property {boolean} pending Whether the call is pending.
 * @property {any | null} result The result of the asynchronous call.
 */

/** @type {State} */

zmts

Про токены, JSON Web Tokens (JWT), аутентификацию и авторизацию. Token-Based Authentication

Last major update: 25.08.2020

• Что такое авторизация/аутентификация
• Где хранить токены
• Как ставить куки ?
• Процесс логина
• Процесс рефреш токенов
• Кража токенов/Механизм контроля токенов

rondy

FWIW: I (@rondy) am not the creator of the content shared here, which is an excerpt from Edmond Lau's book. I simply copied and pasted it from another location and saved it as a personal note, before it gained popularity on news.ycombinator.com. Unfortunately, I cannot recall the exact origin of the original source, nor was I able to find the author's name, so I am can't provide the appropriate credits.

---

Effective Engineer - Notes

• By Edmond Lau
• Highly Recommended 👍
• http://www.theeffectiveengineer.com/

What's an Effective Engineer?

thegitfather

Vanilla JavaScript Quick Reference / Cheatsheet

Just migrated it from Codepen.io to markdown. Credit goes to David Conner.

Working with DOM	Working with JS	Working With Functions
Accessing Dom Elements	Add/Remove Array Item	Add Default Arguments to Function
Grab Children/Parent Node(s)	Add/Remove Object Properties	Throttle/Debounce Functions
Create DOM Elements	Conditionals