The JavaScript escape() Function

Ever come across the JavaScript escape() function and wonder what it's all about? In this article, we'll dive into this lesser-used, but occasionally helpful JavaScript function. The escape() function is not usually in the spotlight when it comes to JavaScript development, but it does come in handy when you need to encode special characters in a string.

Note: The escape() function in JavaScript is deprecated and not recommended for use in modern web development. However, understanding its usage could help in maintaining or refactoring older codebases that still utilize it.

As you'll see later in this article, we recommend you use encodeURIComponent() instead.

What is the escape() Function?

The escape() function in JavaScript is used to encode a string. This function makes a string portable so that it can be transmitted across any network to any computer that supports ASCII characters. When encoding, it takes a string and replaces certain characters with escape sequences.

let str = "Hello, World!";
let result = escape(str);
console.log(result);  // Outputs: Hello%2C%20World%21

In the code above, the escape() function replaces the comma (,) and exclamation mark (!) with %2C and %20, respectively.

Note: The escape sequences are initiated by a '%' sign, followed by two hexadecimal digits representing the ASCII value of the character.

When to Use escape()

Despite its deprecation, you might come across the escape() function in older JavaScript code, particularly when dealing with non-ASCII characters, such as those in URLs or cookies. The escape() function is handy when you need to ensure that these characters are transmitted correctly across the network.

let url = "http://example.com/?name=John&age=20";
let result = escape(url);
console.log(result);  // Outputs: http%3A//example.com/%3Fname%3DJohn%26age%3D20

In this example, the escape() function encodes the URL by replacing certain characters with their corresponding escape sequences.

Limitations and Alternatives

While the escape() function can be useful in some situations, it definitely has limitations. For example, it does not encode characters like +, @, and /, which can cause issues in certain cases, such as when dealing with internationalized domain names, emails, or URLs.

A more suitable alternative to the escape() function is encodeURIComponent(), which encodes special characters, including those ignored by the escape() function.

let url = "http://example.com/?name=John&age=20";
let result = encodeURIComponent(url);
console.log(result);  // Outputs: http%3A%2F%2Fexample.com%2F%3Fname%3DJohn%26age%3D20

The encodeURIComponent() function encodes the forward slash (/), while the escape() function does not.

Conclusion

Even though the JavaScript escape() function is now deprecated, it has had its uses in the past, particularly when dealing with special characters in strings. Knowing how it works can be beneficial when dealing with older codebases. However, for contemporary development tasks, especially those involving URLs or Unicode characters, alternatives like encodeURIComponent() offer a more comprehensive and reliable solution.