Diskette

Diskette is a virtual file format that allows for efficient in-memory reads and writes. Files can be constructed from any buffer or string and they are fully streamable. As a consequence, any buffer or string can be streamed as if it was a regular file.

Projects making use of it:

• Comet

Your project here?

let diskette = require('diskette')
 
let file = new diskette.File({
  blockLength: 20
})
 
file.append('yo bruh\n')
file.append('i heard you like files\n')
file.write(4, 'dude')
 
let rest = new File('so i made files in memory that can be piped to just about anything\n')
let restStream = new diskette.ReadableFileStream(rest)
 
let out = new diskette.WritableFileStream(file)
 
restStream.pipe(out)
 
restStream.on('end', () => {
  file.append('hope you like it')
})
 
let s = new diskette.ReadableFileStream(file)
s.pipe(process.stdout)

Result:

yo dude 
i heard you like files
so i made files in memory that can be piped to just about anything
hope you like it

API

File

new File([content][, options])

Create a new file which has its contents stored in-memory, optionally filled with content, and with one of the following options:

• blockLength: the size of one block

Note: content can be omitted.

file.size

The total length of the file, in bytes.

file.write(position, bufferOrString[, bufferStart][, bufferEnd])

Writes the content of buffer between the given indices to the given position. If no indices are provided, the enitre content of the buffer is written to file.

file.append(bufferOrString[, bufferStart][, bufferEnd])

Just like file.write, except that it appends data to the end of the file.

file.read(position, buffer, bufferStart, bufferEnd)

Reads content of file starting at the given position to the given buffer, optionally limited by two indices denoting the start and the end position of the buffer.

file.buffer([freeSpacePreceding = 0][, freeSpaceFollowing = 0])

Get a buffer that holds the content of file. Optionally make the buffer contain freeSpacePreceding and freeSpaceFollowing of free space.

file.toString([enc])

Convert the file to a string representation, using the specified encoding. Defaults to utf8.

file.allocateBlock()

Allocates a new block for writing content. This method is automatically called by the class, and generally should not be used.

file.totalLength()

Returns the total space the file occupies in-memory, including unused free space.

file.clear()

Clears all content of file by destroying the blocks, making it seem like an empty file was just created.

ReadableFileStream

new ReadableFileStream(file[, options])

Constructs a new readable stream of which data of file can be read. The options are:

• chunkSize: how much data to stream in one cycle. Use -1 to make the chunk as large as possible (possibly the enitre file content). Defaults to -1.
• startPosition: an offset in the file to start reading from. Defaults to 0.

WritableFileStream

new WritableFileStream(file[, options])

Constructs a new writable stream that writes data to file starting at the given position.

Similar projects

• vinyl: only stream or buffer (exclusively)
• node-stream-buffer: only delay in reads and writes