Equivalent of printf or String.Format in JavaScript

David Y.

The 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 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"

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