Trying to capitalize the first character in array of strings, why this is not working?

I'm trying to write a function that converts for example list-style-image to listStyleImage.

I came up with a function but it seems not working. Can anybody point me to the problem here ?

var myStr = "list-style-image";

function camelize(str){
    var newStr = "";    
    var newArr = [];
    if(str.indexOf("-") != -1){
        newArr = str.split("-");
        for(var i = 1 ; i < newArr.length ; i++){
            newArr[i].charAt(0).toUpperCase();
        }       
        newStr = newArr.join("");
    }
    return newStr;
}

console.log(camelize(myStr));

Solution 1:

You have to actually re-assign the array element:

    for(var i = 1 ; i < newArr.length ; i++){
        newArr[i] = newArr[i].charAt(0).toUpperCase();
    }       

The "toUpperCase()" function returns the new string but does not modify the original.

You might want to check to make sure that newArr[i] is the empty string first, in case you get an input string with two consecutive dashes.

edit — noted SO contributor @lonesomeday correctly points out that you also need to glue the rest of each string back on:

         newArr[i] = newArr[i].charAt(0).toUpperCase() + newArr[i].substr(1);

Solution 2:

Here is my solution with ES6. This is an example where I store the days of the week in my array and I uppercase them with for... of loop.

const days = ['sunday', 'monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday'];

for (let day of days) {
    day = day.charAt(0).toUpperCase() + day.substr(1);
    console.log(day);
}

Here is a link to the documentation: for... of loop documentation

Solution 3:

In your for loop, you need to replace the value of newArr[i] instead of simply evaluating it:

for(var i = 1 ; i < newArr.length ; i++){
    newArr[i] = newArr[i].charAt(0).toUpperCase() + newArr[i].substr(1);
}