Equivalent of printf or String.Format in JavaScript

David Y.

—October 15, 2023

The ProblemThe Problem

In JavaScript, how can I print strings containing the values of variables? I would use printf() to do this in C or PHP and string.Format() to do this in C# or String.format() in Java. What is the JavaScript equivalent of these functions?

The SolutionThe Solution

Modern JavaScript supports template strings delimited with backticks, which can contain arbitrary JavaScript expressions inside one or more ${} blocks. For example:

const myNum = 20;
const myString = `The value of myNum is ${myNum}`;
const myString2 = `The value of myNum + 10 is ${myNum + 10}`;

console.log(myString); // will print "The value of myNum is 20"
console.log(myString2); // will print "The value of myNum + 10 is 30"