JavaScript byte to string

JavaScript is a widely used programming language, which is especially common in front-end development and can achieve various interactive effects and animations. In JavaScript development, it is sometimes necessary to convert binary bytes into strings to facilitate data processing and transmission. This article will explain how to convert bytes to string in JavaScript.

1. The concepts of bytes and strings

In computers, byte (byte) is the smallest storage unit in the computer. One byte is usually represented by eight binary bits, that is $2^8=256$ different combinations. A byte can represent a character or a number, or any data such as pictures, sounds, videos, etc.

A string is a text composed of a series of characters, which can include letters, numbers, symbols and spaces. In JavaScript, strings can be represented by enclosing them in single or double quotes.

2. Conversion method of bytes and strings

In JavaScript, there are two methods to convert bytes into strings, namely using TextDecoder object and manual decoding. They will be introduced separately below.

1. Use the TextDecoder object

The TextDecoder object is a built-in object of JavaScript, used to decode the byte stream into a string. Before using the TextDecoder object, the byte stream needs to be stored in a Uint8Array object. The specific code is as follows:

//创建一个包含字节流的Uint8Array对象
const bytes = new Uint8Array([65, 66, 67, 68]);

//创建一个TextDecoder对象
const decoder = new TextDecoder();

//解码字节流
const str = decoder.decode(bytes);

//输出结果
console.log(str); //"ABCD"

In the above code, we first create a Uint8Array object containing four bytes. The bytes contained are 65, 66, 67 and 68 respectively, and the corresponding ASCII codes are respectively are "A", "B", "C" and "D". Then a TextDecoder object is created, and finally the decode method is called to decode the byte stream and the result is stored in the variable str. The output result is "ABCD", that is, the byte stream is converted into a string.

2. Manual decoding

In JavaScript, we can also manually decode the byte stream and convert it into a string. The specific code is as follows:

//创建一个包含字节流的Uint8Array对象
const bytes = new Uint8Array([65, 66, 67, 68]);

//手动解码字节流
let str = "";
for(let i = 0; i < bytes.length; i++){
  str += String.fromCharCode(bytes[i]);
}

//输出结果
console.log(str); //"ABCD"

In the manual decoding method, we first create a Uint8Array object containing four bytes, which also contains the ASCII codes "A", "B", and "C" and "D" characters. Then loop through each byte in the byte stream, convert it to the corresponding character using the fromCharCode method, and concatenate all characters into a string. The final output result is "ABCD", which also converts the byte stream into a string.

3. Use different encoding methods

In actual scenarios, it is often necessary to convert byte streams of different encoding methods into strings. For example, in HTTP communication, the transmitted data may be a UTF-8 encoded byte stream or a GB2312 encoded byte stream. Different encoding methods may affect the conversion results, so you need to specify the correct encoding method when performing byte conversion.

In the TextDecoder object, you can specify the encoding method by modifying the configuration options. The following are common encoding methods:

• UTF-8: Commonly used Unicode encoding method, compatible with all character sets. In TextDecoder, use "utf-8" or "UTF-8" to specify the UTF-8 encoding method.
• GB2312: Chinese encoding method, suitable for Simplified Chinese. In TextDecoder, use "gb2312" or "GBK" to specify the GB2312 encoding method.
• ISO-8859-1: Western European character set encoding. In TextDecoder, use "iso-8859-1" or "ISO-8859-1" to specify the ISO-8859-1 encoding method.

For example, the code to convert a UTF-8 encoding byte stream into a string is as follows:

//创建一个包含UTF-8编码方式的字节流的Uint8Array对象
const bytes = new Uint8Array([228, 184, 150, 229, 155, 189, 233, 163, 142, 231, 154, 132]);

//创建一个TextDecoder对象，指定UTF-8编码方式
const decoder = new TextDecoder("utf-8");

//解码字节流
const str = decoder.decode(bytes);

//输出结果
console.log(str); //"你好世界"

In the above code, we first create a file containing UTF-8 Uint8Array object encoding the byte stream. Then a TextDecoder object is created and the encoding method is specified by passing the "utf-8" parameter. Finally, the decode method is called to decode the byte stream, and the result is stored in the variable str, and the output result is "Hello World".

4. Conclusion

Conversion of bytes and strings is often encountered in JavaScript development. This article introduces two methods for conversion, including using TextDecoder objects and manual decoding. In addition, this article also introduces common encoding methods and demonstrates how to specify different encoding methods for conversion. By studying this article, readers can have a deeper understanding of the concepts of bytes and strings, master the method of converting bytes into strings, and provide more technical support for JavaScript development.

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