JS Snipets

Number verification

function getPrecioMostrar(price) {
    price = +price // just in case string: convert to nr
    if (typeof price != "number" || isNaN(price)) {
        return ("no es un formato correcto");
    } else {
        return (price.toFixed(2) + " €");  // fixed 2 decimals
    }
}
console.log(getPrecioMostrar("4asd"))

Math

function divide(a, b) {
    return a / b;   
}
console.log(divide(21,7)) // 3

The substring() Method

substring() extracts a part of a string:

let text = "Hello world!";
let result = text.substring(1, 4); // result: ell

The toFixed() Method

toFixed() converts a number to a string, rounded to a specified number of decimals:

let num = 5.56789;
let n = num.toFixed(2);

The split() Method

split() splits a string into an array of substrings, and returns the array:

let text = "How are you doing today?";
const myArray1 = text.split(" ");        //How,are,you,doing,today? 
const myArray2 = text.split(" ", 3);     //How,are,you

The slice() method

slice() extracts a part of a string and returns the extracted part:

let text = "Hello world!";
let result = text.slice(0, 5); // Hello
let result = text.slice(3);    // lo world!

Capitalize a word

const Led = {
    lampara1: "rojo",
    lampara2: "verde",
    lampara3: "azul"
}

const RGB = [
    Led.lampara1.charAt(0).toUpperCase() + Led.lampara1.slice(1),
    Led.lampara2.charAt(0).toUpperCase() + Led.lampara2.slice(1),
    Led.lampara3.charAt(0).toUpperCase() + Led.lampara3.slice(1)
]

ATM Function

const currencies = [500, 200, 100, 50, 20, 10, 5, 2, 1];
const maxCoin = 2;

function getFreshMoney(myMoney) {
  for (let i = 0; i < currencies.length; i++) {
    const currency = currencies[i];
    if (myMoney >= currency) {
      currency > maxCoin ? console.log(`|${currency}eur`) : console.log(`(${currency})eur`);
      if (myMoney -= currency) {
        if (myMoney >= currency) {
          i--; // keeps in the same length in case there are more than 1 of a kind
        }
      }
    }
  }
}
const myMoney = 1498;

getFreshMoney(myMoney);

Promt and string to number

function duplicaNumero() {
  let num = prompt ('Please enter a number');
  num = +num;
  if (isNaN(num)) {
    return ('Is this a number???');
  }
  return num *2;
}
console.log(duplicaNumero());