Flavio Corpa kutyel

Typical JS Interview Questions

What is a Closure?

Closure is when a function "remembers" its lexical scope even when the function is executed outside that lexical scope. (IMO: just a stupid function returning another partially applied function).

What is Hoisting?

Variable and function declarations are put into memory during the compile phase, but stays exactly where you typed it in your coding. There is no physically lifting to the top of the file at all.

Starting code:

const getRanges = compose(
  chain(([x, y]) => range(x, y + 1)),
  map(compose(map(Number), split('..'))),
  match(rangeRegex)
)
const getNumbers = compose(
  chain(identity),
  map(compose(map(Number), split(','))),

	class LinkedList {
	head = null
	tail = null

	add (value) {
	const node = { value, next: null }
	if (!this.head) this.head = node
	if (this.tail) {
	this.tail.next = node
	}

	'use strict'

	require('now-env')
	const Twit = require('twit')
	const Task = require('data.task')
	const Maybe = require('data.maybe')
	const bot = new Twit({
	consumer_key: process.env.CONSUMER_KEY,
	consumer_secret: process.env.CONSUMER_SECRET,
	access_token: process.env.ACCESS_TOKEN,

	const copySort = (array, order, key) =>
	[...array].sort(
	(a, b) => order.findIndex(x => x[key] === a[key]) - order.findIndex(x => x[key] === b[key])
	)
	const order = [{ id: 1 }, { id: 2 }, { id: 3 }, { id: 4 }, { id: 5 }]
	const unordered = [
	{ id: 2, label: 'Two' },
	{ id: 3, label: 'Three' },
	{ id: 5, label: 'Five' },
	{ id: 4, label: 'Four' },

	const foo = { a: 1, b: 2, c: 3 }
	const { x, ...y } = foo // rest properties

	console.log(x) // 1
	console.log(y) // { b: 2, c: 3 }

	const bar = { d: 4, e: 5 }
	const baz = { ...foo, ...bar } // spread properties
	console.log(baz) // { a: 1, b: 2, c: 3, d: 4, e: 5 }

	fetch('http://example/endpoint')
	.then(data => data.json()) // todo bien, todo correcto...
	.catch(err => console.error(err)) // oh oh...
	.finally(() => console.log('...y yo que me alegro!')) // <-- lo nuevo 😎

	function clear_local_branches --description 'Removes all the local branches that have already been merged'
	command git fetch -p; and git branch -vv \| awk '/: gone]/{print $1}' \| xargs git branch -D
	end

	function node_sos --description 'Node plz SAVE ME!!!'
	rm -rf node_modules package-lock.json; and npm install $argv;
	end

	for await (const line of readLines(filePath)) {
	console.log(line)
	}