how to increment the value of a char in Javascript

Question

How do I increment a string "A" to get "B" in Javascript?

function incrementChar(c)
{


}

What do you want to happen if you call `incrementChar('Z')`? — Dai, Oct 02 '13 at 01:35
Possible duplicate of [What is a method that can be used to increment letters?](http://stackoverflow.com/questions/12504042/what-is-a-method-that-can-be-used-to-increment-letters) — SomethingDark, Apr 22 '17 at 03:11

tckmn · Accepted Answer · 2013-10-02T02:27:24.287

10

You could try

var yourChar = 'A'
var newChar = String.fromCharCode(yourChar.charCodeAt(0) + 1) // 'B'

So, in a function:

function incrementChar(c) {
    return String.fromCharCode(c.charCodeAt(0) + 1)
}

Note that this goes in ASCII order, for example 'Z' -> '['. If you want Z to go back to A, try something slightly more complicated:

var alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'.split('')
function incrementChar(c) {
    var index = alphabet.indexOf(c)
    if (index == -1) return -1 // or whatever error value you want
    return alphabet[index + 1 % alphabet.length]
}

edited Oct 02 '13 at 02:27

answered Oct 02 '13 at 01:34

tckmn

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`index + i`, I guess you meant `index + 1`? – plalx Oct 02 '13 at 02:14
@plalx Whoops, yep. That was a typo. Fixed – tckmn Oct 02 '13 at 02:27

score 1 · Answer 2 · answered Jun 15 '14 at 03:12

var incrementString = function(string, count){
    var newString = [];
    for(var i = 0; i < string.length; i++){
        newString[i] = String.fromCharCode(string[i].charCodeAt() + count);
    }
    newString = newString.join('');
    console.log(newString);

    return newString;
}

this function also can help you if you have a loop to go through

how to increment the value of a char in Javascript

2 Answers2

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