What is the Buffer.byteLength function in Node.js?
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The Buffer.byteLength function is used to calculate the size of a pre-declared object of the following kinds of data-structures in bytes:
- String
- Buffer
- TypedArray
- DataView
- ArrayBuffer
- SharedArrayBuffer
Syntax
To use Buffer.byteLength, the following syntax is used:
Buffer.byteLength(string, encoding)
Parameters
The Buffer.byteLength function takes in two arguments:
string- the name of the object to calculate the size of (in bytes)encoding- encoding in which values inside the data-structure are formatted
encodingis an optional parameter
The following illustration lists some of the most commonly used encodings supported by the Buffer.byteLength function.
For an object of type
string, the encoding is assumed to beUTF-8by default.
Return value
It returns the size of the data-structure in bytes.
Example
The following program allocates to buffers that contain the same string.
However, the string in one of the buffers is encoding in UTF-8 and UCS-2 in the other. UCS-2 is a subset of the UTF-16 encoding format supported by Node.js.
In
UCS-2each character is 2 bytes long, and inUTF-8each character is 1 byte long.
Using the Buffer.byteLength function, we calculate the size of the two buffers in bytes. As expected, the size of the second buffer, encoded in UCS-2, is double the size of the first buffer and greater than the number of data elements in it, i.e., 9.
var buffer_utf8 = Buffer.from("Educative",);console.log(buffer_utf8.toString())console.log("Size for the string above encoded in UTF-8:", Buffer.byteLength(buffer_utf8), "bytes")var buffer_utf16 = Buffer.from("Educative", "ucs2");console.log("Size for the same string encoded in UCS-2, which is the subset of UTF-16 supported by Node:",Buffer.byteLength(buffer_utf16), "bytes")
