How to Concatenate a Number to a String in JavaScript

You can concatenate a number to a string using the + operator as shown below.

let example = 'Hello World';

let demo = example + 42; // 'Hello World42'

let reverse = 42 + example; // '42Hello World'

You can also use the String#concat() function, but using the + operator is less error prone in case str isn't a string.

let example = 'Hello World';

example.concat(42); // 'Hello World42'

example = null;
null.concat(42); // Throws a TypeError

Note: If you are simply printing variables to the console, you do not need to concatenate. Instead, use console.log() and pass each value you want to print as an argument:

let example = 'Hello World';
console.log(example, 42); // Prints "Hello World 42", 42 is highlighted as a number

---

More Fundamentals Tutorials

• Calculate the Median of an Array in JavaScript
• The encodeURIComponent() Function in JavaScript
• How to Check if a Date is Between Two Dates in JavaScript
• Check a String for Numbers in JavaScript
• Rename Variables When Using Object Destructuring in JavaScript
• Split on Multiple Characters in JavaScript
• Empty Objects are Truthy in JavaScript?