How to turn buffer into number in nodejs

Buffer is an object used to process binary data in Node.js. It can play an important role in scenarios such as reading and writing network data, file operations, and encryption algorithms. In the process of processing binary data, we sometimes need to convert the Buffer type to other types, such as numeric types. This article will introduce how to convert the Buffer type to a numeric type.

1. Convert Buffer type to hexadecimal string

Before converting Buffer type to numeric type, we need to convert it to hexadecimal first String. This can be achieved by calling the toString() method of the Buffer object, as shown below:

const buf = Buffer.from('abcd', 'utf8');
const hexString = buf.toString('hex'); // "61626364"

In the above code, we first create a Buffer object containing the string 'abcd', and then convert it to sixteen hexadecimal string.

2. Convert hexadecimal string to numeric type

Before converting hexadecimal string to numeric type, we need to understand the numeric type and hexadecimal relationship. In JavaScript, number types are represented in various ways, including decimal, binary, octal, and hexadecimal. Among them, decimal is the default representation. If we want to convert a hexadecimal string to a numeric type, we need to use the parseInt() function and specify the base parameter as 16, as shown below:

const hexString = '61626364';
const num = parseInt(hexString, 16); // 1633837924

In the above code, we will The hexadecimal string '61626364' is converted into the corresponding numeric type 1633837924 and assigned to the variable num.

3. Convert Buffer type directly to numeric type

In addition to converting Buffer type to hexadecimal string and then to numeric type, Node. js also provides a way to directly convert the Buffer type to a numeric type. This can be achieved by using the read method of the Buffer object, as shown below:

const buf = Buffer.from([0x01, 0x02, 0x03, 0x04]);
const num = buf.readUInt32BE(); // 16909060

In the above code, we first create a Buffer object containing the byte sequence [0x01, 0x02, 0x03, 0x04], and then use The readUInt32BE() method converts it to the corresponding unsigned 32-bit integer number. The parameters of the readUInt32BE() method specify the byte order to be read, where BE represents Big Endian.

4. Convert Buffer type to other types of numbers

In addition to the ways to convert Buffer type to hexadecimal string and number types, there are some situations Next, you need to convert it to other types of numbers, such as floating point or signed integer. This can be achieved by using the read method of the Buffer object and specifying the number of bytes to read and the encoding method, as shown below:

const buf = Buffer.from([0x41, 0xb0, 0x00, 0x00]);
const num = buf.readFloatBE(); // 11

In the above code, we first create a sequence containing the bytes [0x41, 0xb0 , 0x00, 0x00] Buffer object, and then use the readFloatBE() method to convert it to the corresponding floating point number. The parameters of the readFloatBE() method specify the byte order and encoding method of reading, where BE represents Big Endian.

In this article, we introduce various ways to convert Buffer type to numeric type, including converting Buffer type to hexadecimal string, converting hexadecimal string to numeric type, Direct conversion of Buffer types to numeric types and conversion of Buffer types to other types of numeric types. By understanding these methods, we can handle binary data more flexibly and further improve the efficiency of Node.js development.

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