Are JavaScript strings immutable? Do I need a "string builder" in JavaScript?


In JavaScript, strings are immutable, which means that once a string is created, you cannot change it. If you want to modify a string, you will need to create a new string that contains the modified version of the original string.

You do not need to use a “string builder” in JavaScript to build up a string incrementally. Instead, you can use string concatenation to combine multiple strings into a single string. For example:

let greeting = 'Hello';
greeting += ', World';
console.log(greeting);  // Output: "Hello, World"

If you need to build up a string from multiple parts and you are concerned about performance, you can use an array and the join method to create the final string. For example:

const parts = ['Hello', ', ', 'World'];
const greeting = parts.join('');
console.log(greeting);  // Output: "Hello, World"

This can be faster than using string concatenation, especially if you have a large number of string parts. However, it is generally not necessary to worry about this unless you are dealing with very large strings or you are working on a performance-critical application.