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Node.js Buffer Module

❮ Built-in Modules


Example

Convert the string "abc" into a stream of binary data:

var buf = Buffer.from('abc');
console.log(buf);
Run example »

Definition and Usage

The buffers module provides a way of handling streams of binary data.

The Buffer object is a global object in Node.js, and it is not necessary to import it using the require keyword.


Syntax

The syntax for creating an empty Buffer of the length 15:

var buf = Buffer.alloc(15);

Buffer Properties and Methods

Method Description
alloc() Creates a Buffer object of the specified length
allocUnsafe() Creates a non-zero-filled Buffer of the specified length
allocUnsafeSlow Creates a non-zero-filled and non-pooled Buffer of the specified length
byteLength() Returns the numbers of bytes in a specified object
compare() Compares two Buffer objects
concat() Concatenates an array of Buffer objects into one Buffer object
copy() Copies the specified number of bytes of a Buffer object
entries() Returns an iterator of "index" "byte" pairs of a Buffer object
equals() Compares two Buffer objects, and returns true if it is a match, otherwise false
fill() Fills a Buffer object with the specified values
from() Creates a Buffer object from an object (string/array/buffer)
includes() Checks if the Buffer object contains the specified value. Returns true if there is a match, otherwise false
indexOf() Checks if the Buffer object contains the specified value. Returns the first occurrence, otherwise -1
isBuffer() Checks if an object is a Buffer object
isEncoding() Checks if the Buffer object supports the specified encoding
keys() Returns an array of keys in a Buffer object
lastIndexOf() Checks if the Buffer object contains the specified value. Returns the first occurrence, starting from the end, otherwise -1
length Returns the length of a Buffer object, in bytes
poolSize Sets or returns the number of bytes used for pooling
readDoubleBE() Reads a 64 bit double from a Buffer object, returns the result in big endian
readDoubleLE() Reads a 64 bit double from a Buffer object, returns the result in little endian
readFloatBE() Reads a 32 bit float from a Buffer object, returns the result in big endian
readFloatLE() Reads a 32 bit float from a Buffer object, returns the result in little endian
readInt8() Reads a 8 bit integer from a Buffer object
readInt16BE() Reads a 16 bit integer from a Buffer object, returns the result in big endian
readInt16LE() Reads a 16 bit integer from a Buffer object, returns the result in little endian
readInt32BE() Reads a 32 bit integer from a Buffer object, returns the result in big endian
readInt32LE() Reads a 32 bit integer from a Buffer object, returns the result in little endian
readIntBE() Reads the specified number of bytes from a Buffer object, returns the result in big endian
readIntLE() Reads the specified number of bytes from a Buffer object, returns the result in little endian
readUInt8() Reads an unsigned 8 bit integer from a Buffer object
readUInt16BE() Reads an unsigned 16 bit integer from a Buffer object, returns the result in big endian
readUInt16LE() Reads an unsigned 16 bit integer from a Buffer object, returns the result in little endian
readUInt32BE() Reads an unsigned 32 bit integer from a Buffer object, returns the result in big endian
readUInt32LE() Reads an unsigned 32 bit integer from a Buffer object, returns the result in little endian
readUintBE() Reads the specified number of bytes from a Buffer object, returns the result as an unsigned integer
readUIntLE() Reads the specified number of bytes from a Buffer object, returns the result as an unsigned integer
slice() Slices a Buffer object into a new Buffer objects starting and ending at the specified positions
swap16() Swaps the byte-order of a 16 bit Buffer object
swap32() Swaps the byte-order of a 32 bit Buffer object
swap64() Swaps the byte-order of a 64 bit Buffer object
toString() Returns a string version of a Buffer object
toJSON() Returns a JSON version of a Buffer object
values() Returns an array of values in a Buffer object
write() Writes a specified string to a Buffer object
writeDoubleBE() Writes the specified bytes, using big endian, to a Buffer object. The bytes should be 64 bit double.
writeDoubleLE() Writes the specified bytes, using little endian, to a Buffer object. The bytes should be 64 bit double.
writeFloatBE() Writes the specified bytes, using big endian, to a Buffer object. The bytes should be 32 bit float.
writeFloatLE() Writes the specified bytes, using little endian, to a Buffer object. The bytes should be 32 bit float.
writeInt8() Writes the specified bytes to a Buffer object. The bytes should be 8 bit integer
writeInt16BE() Writes the specified bytes, using big endian, to a Buffer object. The bytes should be 16 bit integer.
writeInt16LE() Writes the specified bytes, using little endian, to a Buffer object. The bytes should be 16 bit integer.
writeInt32BE() Writes the specified bytes, using big endian, to a Buffer object. The bytes should be 32 bit integer.
writeInt32LE() Writes the specified bytes, using little endian, to a Buffer object. The bytes should be 32 bit integer.
writeIntBE() Writes the specified bytes, using big endian, to a Buffer object.
writeIntLE() Writes the specified bytes, using little endian, to a Buffer object.
writeUInt8() Writes the specified bytes to a Buffer object. The bytes should be 8 bit unsigned integer
writeUInt16BE() Writes the specified bytes, using big endian, to a Buffer object. The bytes should be 16 bit unsigned integer.
writeUInt16LE() Writes the specified bytes, using little endian, to a Buffer object. The bytes should be 16 bit unsigned integer.
writeUInt32BE() Writes the specified bytes, using big endian, to a Buffer object. The bytes should be 32 bit unsigned integer.
writeUInt32LE() Writes the specified bytes, using little endian, to a Buffer object. The bytes should be 32 bit unsigned integer.
writeUIntBE() Writes the specified bytes, using big endian, to a Buffer object
writeUIntLE() Writes the specified bytes, using little endian, to a Buffer object

❮ Built-in Modules