What's the StringBuilder equivalent in TypeScript?

Question

So I have this string that contains a percentage symbol %. I want to be able to replace it with the # symbol using TypeScript. I am still learning TypeScript so it's syntax is still throwing me off. I managed to implement the solution that I need in C# and that piece of code can be found below:

 public static void Main(string[] args)
 {
     string data = "AHu%odk"; //The % character will always be at index 3
     string finalResult = "";
     if (data.Contains("%"))
     {
          StringBuilder sbFirstIndex = new StringBuilder(data);
          sbFirstIndex[3] = '#'; 
          finalResult = sbFirstIndex.ToString();
          Console.WriteLine("Appended string now looks like this: {0} \n", finalResult);
     }
     else
     {
           Console.WriteLine("False. It does not contain it");
     }
 }

Here is my TypeScript implementation but I got stuck if checking for the index of the character:

changePercantage(input: string): void {
    var data= "AHu%odk";
    var finalResult = ""; 
    var index = result.indexOf("%");

    if (index == 3) { 
        //Replace the percentage with the # character
    }
}

The version of TypeScript that I am using is v2.3.3.0.

Angular : v5.0.0

Node: v8.9.3

Npm: v5.6.0

Solution

In Typescript, for string replacement, use RegExp

function changePercentage(input) {
    return input.replace(/%/, "#");
}

console.log(changePercentage("AHu%odk"));

Comments

[Harold_Finch]

You come to my rescue again in the same day! Thank you :-)

[Abhijit Kar ツ]

@Harold_Finch, my pleasure!