How to get string size in bytes in javascript(examples)

How to get string size in bytes in javascript(examples)

Different ways to find string size or length in bytes In Javascript

  • nodejs buffer object, an example is Buffer.byteLength("str", 'utf8'))
  • Using Blob object, new Blob([str]).size
  • TextEncoder encoder method, new TextEncoder().encode(str).length
  • unescape method,unescape(encodeURIComponent(str)).length

A string in JavaScript is a group of characters, Each character holds 16 bits of an integer. Each string stores the data in memory, as we don’t have a direct method like sizeof in a c programming language.

You can check my other post on Javascript check substring exists in a String Let’s declare the input string.

var str = "a";
var str1 = "ab";
var str2 = "aabc";
var str3 = "🙂";
var str4 = "👍🙂";

input one character returns 1 byte in characters, whereas ”ab” returns 2 bytes. However, emojis return 4 bytes for each symbol, and two emojis return 8 bytes.

Emojis are UTF encoding strings that use 4 bytes to represent a character.

The output of the above input is

1;
2;
4;
4;
6;

Use nodejs buffer object

Buffer🔗 is an inbuilt object in NodeJS programming, used to store the fixed bytes.

Buffer’s byteLength method returns string size in bytes with a given encoding.

Here is a syntax

Buffer.byteLength(String, encoding);
  • String - string raw data
  • encoding - UTF-8 or UTF-16

It returns String size in bytes.

console.log(Buffer.byteLength(str, "utf8")); // 1
console.log(Buffer.byteLength(str1, "utf8")); // 2
console.log(Buffer.byteLength(str2, "utf8")); // 4
console.log(Buffer.byteLength(str3, "utf8")); // 4
console.log(Buffer.byteLength(str4, "utf8")); // 8

This approach works in the latest browsers and is widely used on the Client and server side.

Use Blob object

Blob🔗 is a javascript inbuilt object, used to get binary data of any type of file.

The file can be images or string text. Create a Blob object using String, called Blob.size property returns the size of a string.

console.log(new Blob([str]).size); // 1
console.log(new Blob([str1]).size); // 2
console.log(new Blob([str2]).size); // 4
console.log(new Blob([str3]).size); // 4
console.log(new Blob([str4]).size); // 8

Use TextEncoder encode function

TextEncoder🔗 is a function used by web workers to return the string data in bytes The encode method returns the encoded object and the length returns in bytes

console.log(new TextEncoder().encode(str).length);
console.log(new TextEncoder().encode(str1).length);
console.log(new TextEncoder().encode(str2).length);
console.log(new TextEncoder().encode(str3).length);
console.log(new TextEncoder().encode(str4).length);

Use the unescape length method

unescape🔗 is an object going to be deprecated. It is used in encoding the string.

However, the length method of the unescape object can return the string data in bytes.

console.log(unescape(encodeURIComponent(str)).length);
console.log(unescape(encodeURIComponent(str1)).length);
console.log(unescape(encodeURIComponent(str2)).length);
console.log(unescape(encodeURIComponent(str3)).length);
console.log(unescape(encodeURIComponent(str4)).length);

Conclusion

To Sum Up, There are several methods documented in this post to return the string size in bytes. You can choose the appropriate one based on your needs.