Padding Strings in JavaScript

Introduction

In this lab, we will explore the pad() function in JavaScript. The pad() function allows you to pad a string on both sides with a specified character to achieve a certain length. We will learn how to use the String.prototype.padStart() and String.prototype.padEnd() methods to achieve this.

Skills Graph

Function to Pad String

To pad a string on both sides with the specified character, if it's shorter than the specified length, use the following function:

const pad = (str, length, char = " ") =>
  str.padStart((str.length + length) / 2, char).padEnd(length, char);

The function uses String.prototype.padStart() and String.prototype.padEnd() to pad both sides of the given string. You can omit the third argument, char, to use the whitespace character as the default padding character.

Here are some examples of how to use the pad() function:

pad("cat", 8); // '  cat   '
pad(String(42), 6, "0"); // '004200'
pad("foobar", 3); // 'foobar'

To start practicing coding, open the Terminal/SSH and type node.

Summary

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