djD-REK

console.log(typeof 37) // "number"
console.log(typeof 2.71828) // "number"
console.log(typeof Math.E) // "number"
console.log(typeof Infinity) // "number"

// The typeof NaN is "number" even though NaN means "Not-A-Number":
console.log(typeof NaN) // "number"

// Calling Number explicitly is one way to parse a number:
console.log(typeof Number(`1`)) // "number"

djD-REK

console.log("Hello world!".padStart(20))
console.log("Goodnight moon!".padStart(20))
// Output:
//        Hello world!
//     Goodnight moon!

djD-REK

"Pizza".padEnd(30,".")+"$19.99"
// "Pizza.........................$19.99"

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const menuItem = (item, price) => item+price.padStart(40-item.length,".")

console.log(menuItem("Pizza","$19.99"))
console.log(menuItem("Soda","$2.99"))
console.log(menuItem("Greek Salad","$9.99"))

// Output:
// Pizza.............................$19.99
// Soda...............................$2.99
// Greek Salad........................$9.99

djD-REK

import React, { useState } from "react"
import ReactDOM from "react-dom"

import "./styles.css"

function App() {
  // React Hooks declarations
  const [searches, setSearches] = useState([])
  const [query, setQuery] = useState("")

djD-REK

import React, { useState } from "react"
import ReactDOM from "react-dom"

function App() {
  // React Hooks declarations
  const [searches, setSearches] = useState([])
  const [query, setQuery] = useState("")
  
  const handleClick = () => {
    // Save search term state to React Hooks

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let array = ["😜"]
array.push("😂")
console.log(array) // Array [ "😜", "😂" ]

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setSearches([query].concat(searches)) // prepend to React State

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/**
 * First checks typeof, then self-equality to make sure it is
 * not NaN, then to make sure it is not Infinity or -Infinity.
 *
 * @param {*} value - The value to check
 * @return {boolean} Whether that value is a number
 */
const isNumber = value => {
  // First: Check typeof and make sure it returns number
  // This code coerces neither booleans nor strings to numbers,

djD-REK

/**
 * Check whether the value is a JavaScript number.
 *
 * First checks typeof, then self-equality to make sure it is
 * not NaN, then for equality to Infinity or -Infinity.
 *
 * @param {*} value - The value to check
 * @return {boolean} Whether that value is a number
 */
const isNumber = value => typeof value === 'number' && value === value && value !== Infinity && value !== -Infinity