String Manipulation in Javascript?

Question

I have the following code

var wcalcAlm = ('0140')
alert(wcalcAlm)
//retorno esperado ('01:40')

I need that after the 2 position of the variable wcalcAlm be included :, thus having the following return 01:40?

Answer 1

Just do the following:

function adicionarTexto(str, caracter, indice){
  return str.slice(0, indice) + caracter + str.slice(indice)
}

var wcalcAlm = ('0140')
console.log(adicionarTexto(wcalcAlm, ':', 2))

This adds a character (or a string) from the index you send.

Answer 2

You have this solution:

wcalcAlm.replace(/(\d{2})/,'$1:');

• replace will go through the whole amount.
• /(\d{2})/ with Regex I will take the digits and break in the second position.
• after having separated it creates a mask after the first group, with the character :.
• and gathered in the way expected.

var wcalcAlm = ('0140');
console.log(wcalcAlm.replace(/(\d{2})/,'$1:'));

Answer 3

Another way:

//Duas linhas:
var wcalcAlm = ('0140').split("");
console.log(wcalcAlm[0] + wcalcAlm[1] + ":" + wcalcAlm[2] + wcalcAlm[3]);

Answer 4

I’ll put two more options on how we can achieve the desired result:

//Opção com array
const arr = '0140'.split('');
arr.splice(2,0,':');

console.log(arr.join(''));

//Opção com regex
let i = 0;
console.log('##:##'.replace(/#/g, () => '0140'[i++]));