How to modify strings in js array

Question

It was supposed to capitalize first characters of each string but it doesn't. Please tell me how I can solve this problem.

    let array = ["string1", "string2", "string3", "string4"];
    let btn = document.getElementById("btn");

    array.forEach(function (item) {
      item.charAt(0).toUpperCase();
    })

    btn.addEventListener("click", function () {
      document.getElementById("p").innerHTML = array.join(" ")
    })```

You've to create a new string in the loop, strings in JS are immutable. — Teemu, Jan 19 '22 at 20:05

score -1 · Answer 1 · answered Jan 19 '22 at 20:08

You are getting the first letter and converting it to uppercase, but you aren't doing anything with it.

You need to concatenate the rest of the string to the first character, then reassign back.

let array = ["string1", "string2", "string3", "string4"];

array.forEach(function(item, i) {
  array[i] = item.charAt(0).toUpperCase() + item.substring(1)
})

console.log(array.join(" "))

How to modify strings in js array

1 Answers1