@mojule/vfs-core

vfs-core

Virtual file system built on mojule tree

This is the core of VFS - there is no way to interact with underlying filesystem - this functionality is provided by @mojule/vfs

Important: this documentation is out of date and needs to be updated. However, the tests are up to date and provide examples for usage.

Install

npm install @mojule/vfs

Example

const Vfs = require( '@mojule/vfs' )

const tree = Vfs.virtualize( 'some/path' )

console.log( tree.serialize() )

const virtualFile = Vfs.createFile( 'hello.txt', 'Hello, World!', 'utf8' )
const virtualDirectory = Vfs.createDirectory( 'text' )

virtualDirectory.appendChild( virtualFile )
virtualDirectory.actualize( 'some/path' )

Plugins

vfs has the same API as mojule tree but with the following plugins:

createFile

Creates a file node. The arguments are the same as fs.writeFile:

Vfs.createFile( filename, data, encoding )

encoding is optional, but if included should be a valid node.js encoding type

If encoding is omitted, it will assume 'utf8' if data is a string, or if data is a Buffer, a JSON buffer representation or an array of bytes it will assume convert data to a buffer.

// { type: 'Buffer', data: [ 1, 2, 3 ] }
const jsonObj = JSON.parse( JSON.stringify( Buffer.from( [ 1, 2, 3 ] ) ) )

const text1 = Vfs.createFile( 'hello.txt', 'hello' )
const text2 = Vfs.createFile( 'hello.txt', 'hello', 'utf8' )
const data1 = Vfs.createFile( 'hello.bin', [ 1, 2, 3 ] )
const data2 = Vfs.createFile( 'hello.bin', Buffer.from( [ 1, 2, 3 ] ) )
const data3 = Vfs.createFile( 'hello.bin', jsonObj )

createDirectory

Creates a directory node

Vfs.createDirectory( filename )

const hello = Vds.createDirectory( 'hello' )
const world = Vfs.createFile( 'world.txt', 'world' )

hello.append( world )

actualize

Writes a vfs tree to disk, then calls callback with the error if one occured

node.actualize( targetPath, callback )

The directories and files in your virtual file system will be written under targetPath - node.js will throw an error if any of the files or directories already exist, so you may want to clear it out first if this may be the case.

const hello = Vds.createDirectory( 'hello' )
const world = Vfs.createFile( 'world.txt', 'world' )

hello.append( world )

hello.actualize( './temp', err => {
  if( err ) return console.error( err )

  console.log( 'wrote vfs to ./temp' )
})

atPath

Gets the node at a given path in the tree. Overrides the base atPath to match paths that match those provided by getPath, see below for more information

const hello = Vds.createDirectory( 'hello' )
const world = Vfs.createFile( 'world.txt', 'world' )

hello.append( world )

const target = hello.atPath( 'hello/world.txt' )

// true
console.log( world === target )

getPath

Overrides the base getPath to return paths that map 1:1 to a file system - eg the slug for the root node will be included in the path, unlike the default implementation in which it is instead implied. Unlike the base getPath, does not take a separator - posix style paths eg / are used.

const hello = Vds.createDirectory( 'hello' )
const world = Vfs.createFile( 'world.txt', 'world' )

hello.append( world )

// 'hello/world.txt'
console.log( world.getPath() )

isEmpty

Overrides the default implementation, and returns true for nodes with nodeType of file, false for nodes with nodeType of directory

If you try to add a child node to a file it will throw

const hello = Vds.createDirectory( 'hello' )
const world = Vfs.createFile( 'world.txt', 'world' )

// false
console.log( hello.isEmpty() )

// true
console.log( world.isEmpty() )

isValue

Overrides the default implementation, which simply returns true if the node's value is an object, and only returns true if the combination of nodeType, filename, data, encoding etc. are all correct. Constructing nodes with Vfs.createFile and Vfs.createDirectory is suggested to help ensure that this is the case. Used internally to throw whenever you attempt to set the value or any of its properties to something invalid.

const nodeValue1 = {
  nodeType: 'file',
  filename: 'hello.txt',
  data: 'hello'
}

// true
console.log( Vfs.isValue( nodeValue1 ) )

const nodeValue2 = {
  nodeType: 'file',
  filename: 'temp/hello.txt',
  data: 'hello'
}

// false - file name contains a reserved character, /
console.log( Vfs.isValue( nodeValue2 ) )

nodeType

Overridden from the default (always returns the string 'node') to return the nodeType property of the node's value object - will always be either file or directory

const hello = Vds.createDirectory( 'hello' )
const world = Vfs.createFile( 'world.txt', 'world' )

// 'directory'
console.log( hello.nodeType() )

// 'file'
console.log( world.nodeType() )

serializer

Serializes to and from a compact representation suitable for storing as JSON etc

serialize

Serialize the current node

const hello = Vds.createDirectory( 'hello' )
const world = Vfs.createFile( 'world.txt', 'world' )

const serialized = hello.serialize()

{
  "hello/world.txt": "world"
}

deserialize

Deserializes the object to a vfs tree

const data = {
  "hello/world.txt": "world"
}

const hello = Vfs.deserialize( data )
const world = hello.firstChild()

// 'directory'
console.log( hello.nodeType() )

// 'file'
console.log( world.nodeType() )

slug

Overridden from the default to always returns the file or directory's name. Used by getPath.

const hello = Vds.createDirectory( 'hello' )
const world = Vfs.createFile( 'world.txt', 'world' )

// 'hello'
console.log( hello.slug() )

// 'world.txt'
console.log( world.slug() )

virtualize

Reads a file or directory from disk and creates a vfs tree. The callback takes an error if one occurred and the tree if successful.

Vfs.virtualize( sourcePath, callback )

Vfs.virtualize( 'some/path', ( err, tree ) => {
  if( err ) return console.error( err )

  console.log( tree.serialize() )
})

registerText

Registers a text extension with vfs - files with this extension will be treated as text when encoding is not specified and no matching mime type can be found

Vfs.registerText( '.mmon' )

// true
console.log( Vfs.isTextExtension( '.mmon' ) )