How to Concatenate a Number to a String in JavaScript

Jul 1, 2021

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

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