What is readInt32LE() Buffer module in Node.js?
Buffer objects are used to represent a sequence of bytes of pre-determined size. They are similar to arrays but cannot be resized. Since the Buffer class is designed to handle raw binary data, it provides various methods, particularly for binary data.
The readInt32LE method is used to read a signed, little-endian 32-bit integer at an offset provided in the function’s arguments. The bytes read from the buffer are represented as a two’s complement signed integer value.
Syntax and parameters
The method can be accessed using the . notation on a buffer object. In the following example, buf is a Buffer object.
buf.readInt32LE([offset])
- Offset is the number of bytes required to skip before reading the buffer. It is initialized with 0 by default. The offset must be between
0and(buf.length - 4).
buf.lengthis the size of the buffer, i.e., the number of elements in the buffer.
Return value
The function returns a two’s complement signed integer.
Example
We will demonstrate how to use the readInt32LE in the following example:
const buf = Buffer.from([0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70, 0x80]);console.log(buf.readInt32LE(0).toString(16));console.log(buf.readInt32LE(1).toString(16));//console.log(buf.readInt32LE(5).toString(16));
- We first initialize the buffer using an array of hexadecimal numbers and the
.frommethod of theBufferobject. - In line 3, the offset is set to 0. The first 4 values are printed in the reverse order, as little-endian is an order in which the least significant value is stored first.
- In line 4, we provide an offset of 1. The first value is skipped, while the next 4 values are printed in the little-endian order.
- You can comment out line 5 to check that the compiler throws an
ERR_OUT_OF_RANGE(out of range) error when the offset is greater than the limit we described above in the heading “Syntax and parameters.”
The toString method converts the result into text. We provide 16 as the
radixargument of the function to convert the result into a hexadecimal representation.
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