Reverse a String in TypeScript

Reversing a string involves changing the order of its characters, so the last character becomes the first, and vice versa. In TypeScript, there are various methods to achieve this, depending on the developer's preference and the specific requirements of the task.

Method 1: Using a Loop

This method utilizes a loop to iterate through the characters of the string in reverse order, building the reversed string. It is a more traditional approach and may be preferred in scenarios where simplicity and explicit control over the iteration are desired.

Example: In this example, a string "Geeks For Geeks" and is reversed using the a loop.

function reverseStringUsingLoop(str: string): string {
    let reversed = '';
    for (let i = str.length - 1; i >= 0; i--) {
        reversed += str[i];
    }
    return reversed;
}

const reversedStringLoop = 
    reverseStringUsingLoop('Geeks For Geeks');
console.log(reversedStringLoop);

Output:

skeeG roF skeeG

Method 2: Using Array Methods (reverse,split and join)

This method leverages the array functions split, reverse, and join to convert the string into an array of characters, reverse the array, and then join it back into a string. It is a concise and readable approach that takes advantage of the built-in array methods.

Example: In this example, a string "Geeks For Geeks" and is reversed using the array methods.

function reverseStringUsingArray(str: string): string {

    // Convert the string to an array 
    // of characters, reverse it, 
    //and join back to a string
    return str.split('').reverse().join('');
}

const reversedStringLoop = 
    reverseStringUsingArray('Geeks For Geeks');
console.log(reversedStringLoop);

Output:

skeeG roF skeeG

Method 3: Using reduce

This method employs the reduce function to accumulate the reversed string. It iterates through the characters of the string, prepending each character to the accumulating reversed string.

Example: In this example, a string "Geeks For Geeks" and is reversed using the reduce method.

function reverseStringUsingReduce(str: string): string {
  // using reduce with split functions
    return str.split('')
        .reduce((reversed, char) => char + reversed, '');
}

const reversedStringReduce = 
    reverseStringUsingReduce('Geeks For Geeks');
console.log(reversedStringReduce); 

Output:

skeeG roF skeeG