Fs

Utilities for high-level file system interactions. Utilizes WASI Preview 1 for underlying API

Added in 0.7.0

No other changes yet.

from "fs" include Fs

Fs.Utf8.readFile(Path.fromString("baz.txt"))

Fs.Utf8.writeFile(Path.fromString("baz.txt"), "Hello World\n")

Fs.copy(Path.fromString("foo.txt"), Path.fromString("foocopy.txt"))

Types

Type declarations included in the Fs module.

Fs.FileError

enum FileError {
  NoPreopenedDirectories,
  PermissionDenied,
  AddressInUse,
  AddressNotAvailable,
  AddressFamilyNotSupported,
  ResourceUnavailableOrOperationWouldBlock,
  ConnectionAlreadyInProgress,
  BadFileDescriptor,
  BadMessage,
  DeviceOrResourceBusy,
  OperationCanceled,
  NoChildProcesses,
  ConnectionAborted,
  ConnectionRefused,
  ConnectionReset,
  ResourceDeadlockWouldOccur,
  DestinationAddressRequired,
  MathematicsArgumentOutOfDomainOfFunction,
  FileExists,
  BadAddress,
  FileTooLarge,
  HostIsUnreachable,
  IdentifierRemoved,
  IllegalByteSequence,
  OperationInProgress,
  InterruptedFunction,
  InvalidArgument,
  IOError,
  SocketIsConnected,
  IsADirectory,
  TooManyLevelsOfSymbolicLinks,
  FileDescriptorValueTooLarge,
  TooManyLinks,
  MessageTooLarge,
  FilenameTooLong,
  NetworkIsDown,
  ConnectionAbortedByNetwork,
  NetworkUnreachable,
  TooManyFilesOpenInSystem,
  NoBufferSpaceAvailable,
  NoSuchDevice,
  NoSuchFileOrDirectory,
  ExecutableFileFormatError,
  NoLocksAvailable,
  NotEnoughSpace,
  NoMessageOfTheDesiredType,
  ProtocolNotAvailable,
  NoSpaceLeftOnDevice,
  FunctionNotSupported,
  TheSocketIsNotConnected,
  NotADirectoryOrASymbolicLinkToADirectory,
  DirectoryNotEmpty,
  StateNotRecoverable,
  NotASocket,
  NotSupportedOrOperationNotSupportedOnSocket,
  InappropriateIOControlOperation,
  NoSuchDeviceOrAddress,
  ValueTooLargeToBeStoredInDataType,
  PreviousOwnerDied,
  OperationNotPermitted,
  BrokenPipe,
  ProtocolError,
  ProtocolNotSupported,
  ProtocolWrongTypeForSocket,
  ResultTooLarge,
  ReadOnlyFileSystem,
  InvalidSeek,
  NoSuchProcess,
  ConnectionTimedOut,
  TextFileBusy,
  CrossDeviceLink,
  ExtensionCapabilitiesInsufficient,
  UnknownFileError(Number),
}

Potential errors that can be raised from system interactions.

Fs.SpecialFileType

enum SpecialFileType {
  Unknown,
  BlockDevice,
  CharacterDevice,
  SocketDatagram,
  SocketStream,
}

Represents non-standard system file types.

Fs.FileType

enum FileType {
  File,
  Directory,
  SymbolicLink,
  Special(SpecialFileType),
}

Represents different system file types.

Fs.Stats

record Stats {
  fileType: FileType,
  size: Number,
  accessedTimestamp: Number,
  modifiedTimestamp: Number,
  changedTimestamp: Number,
}

Represents metadata about a file.

Fields:

name	type	description
`fileType`	`FileType`
`size`	`Number`	File size in bytes
`accessedTimestamp`	`Number`	Last accessed timestamp in nanoseconds
`modifiedTimestamp`	`Number`	Last modified timestamp in nanoseconds
`changedTimestamp`	`Number`	Last file status change timestamp in nanoseconds

Fs.DirectoryEntry

record DirectoryEntry {
  name: String,
  fileType: FileType,
}

Represents information about an item in a directory.

Fs.RemoveMode

enum RemoveMode {
  RemoveFile,
  RemoveEmptyDirectory,
  RemoveRecursive,
}

The type of removal operation to perform when calling remove.

Fs.CopyMode

enum CopyMode {
  CopyFile,
  CopyRecursive,
}

The type of copy operation to perform when calling copy.

Fs.WriteMode

enum WriteMode {
  Truncate,
  Append,
}

The type of write operation to perform when calling writeFile.

Values

Functions and constants included in the Fs module.

Fs.remove

Added in 0.7.0

No other changes yet.

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remove:
  (?removeMode: RemoveMode, ?baseDirPath: Option<Path.Path>, path: Path.Path) =>
   Result<Void, FileError>

Removes a file or directory.

Parameters:

param	type	description
`?removeMode`	`RemoveMode`	The type of removal to perform; `RemoveFile` by default
`?baseDirPath`	`Option<Path.Path>`	The path to the directory in which path resolution starts
`path`	`Path.Path`	The path of the file or directory to remove

Returns:

type	description
`Result<Void, FileError>`	`Ok(void)` if the operation succeeds, `Err(err)` if a file system error is encountered

Examples:

Fs.remove(Path.fromString("file.txt")) // removes a file

Fs.remove(removeMode=Fs.RemoveEmptyDirectory, Path.fromString("dir")) // removes an empty directory

Fs.remove(removeMode=Fs.RemoveRecursive, Path.fromString("dir")) // removes the directory and its contents

Fs.readDir

Added in 0.7.0

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readDir:
  (?baseDirPath: Option<Path.Path>, path: Path.Path) =>
   Result<List<DirectoryEntry>, FileError>

Reads the contents of a directory.

Parameters:

param	type	description
`?baseDirPath`	`Option<Path.Path>`	The path to the directory in which resolution should begin
`path`	`Path.Path`	The path to the directory to read

Returns:

type	description
`Result<List<DirectoryEntry>, FileError>`	`Ok(contents)` containing the directory contents or `Err(err)` if a file system error is encountered

Fs.createDir

Added in 0.7.0

No other changes yet.

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createDir:
  (?baseDirPath: Option<Path.Path>, path: Path.Path) =>
   Result<Void, FileError>

Creates a new empty directory at the given path.

Parameters:

param	type	description
`?baseDirPath`	`Option<Path.Path>`	The path to the directory in which resolution should begin
`path`	`Path.Path`	The path to create the new directory, relative to the base directory

Returns:

type	description
`Result<Void, FileError>`	`Ok(void)` if the operation succeeds, `Err(err)` if a file system error is encountered

Fs.createSymlink

Added in 0.7.0

No other changes yet.

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createSymlink:
  (linkContents: Path.Path, ?targetBaseDirPath: Option<Path.Path>,
   targetPath: Path.Path) => Result<Void, FileError>

Creates a new symbolic link with the given contents.

Parameters:

param	type	description
`linkContents`	`Path.Path`	The path to store into the link
`?targetBaseDirPath`	`Option<Path.Path>`	The path to the directory in which the target path resolution starts
`targetPath`	`Path.Path`	The path to the target of the link

Returns:

type	description
`Result<Void, FileError>`	`Ok(void)` if the operation succeeds, `Err(err)` if a file system error or relativization error is encountered

Fs.stats

Added in 0.7.0

No other changes yet.

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stats:
  (?followSymlink: Bool, ?baseDirPath: Option<Path.Path>, path: Path.Path) =>
   Result<Stats, FileError>

Queries information about a file.

Parameters:

param	type	description
`?followSymlink`	`Bool`	Whether to follow symlinks or not; if `true` then the stats of a valid symlink’s underlying file will be returned. `true` by default
`?baseDirPath`	`Option<Path.Path>`	The path to the directory in which the path resolution starts
`path`	`Path.Path`	The path of the file to query

Returns:

type	description
`Result<Stats, FileError>`	`Ok(stats)` containing metadata or `Err(err)` if a file system error is encountered

Fs.exists

Added in 0.7.0

No other changes yet.

exists: (?baseDirPath: Option<Path.Path>, path: Path.Path) => Bool

Polls whether or not a file or directory exists at the given path.

Parameters:

param	type	description
`?baseDirPath`	`Option<Path.Path>`	The path to the directory in which the path resolution starts
`path`	`Path.Path`	The path of the file to query

Returns:

type	description
`Bool`	`true` if a file or directory exists at the path or `false` otherwise

Fs.readLink

Added in 0.7.0

No other changes yet.

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readLink:
  (?baseDirPath: Option<Path.Path>, path: Path.Path) =>
   Result<Path.Path, FileError>

Reads the contents of a symbolic link.

Parameters:

param	type	description
`?baseDirPath`	`Option<Path.Path>`	The path to the directory to begin path resolution
`path`	`Path.Path`	The path to the link to read

Returns:

type	description
`Result<Path.Path, FileError>`	`Ok(path)` containing the link contents or `Err(err)` if a file system error is encountered

Fs.copy

copy:
  (?copyMode: CopyMode, ?followSymlink: Bool,
   ?sourceBaseDirPath: Option<Path.Path>, sourcePath: Path.Path,
   ?targetBaseDirPath: Option<Path.Path>, targetPath: Path.Path) =>
   Result<Void, FileError>

Copies a file or directory.

Parameters:

param	type	description
`?copyMode`	`CopyMode`	The type of copy to perform; `CopyFile` by default
`?followSymlink`	`Bool`	Whether to follow symlinks or not; if `true` then the stats of a valid symlink’s underlying file will be returned. `true` by default
`?sourceBaseDirPath`	`Option<Path.Path>`	The path to the directory in which the source path resolution starts
`sourcePath`	`Path.Path`	The path of the file or directory to copy
`?targetBaseDirPath`	`Option<Path.Path>`	The path to the directory in which the target path resolution starts
`targetPath`	`Path.Path`	The path to copy the file or directory to

Returns:

type	description
`Result<Void, FileError>`	`Ok(void)` if the operation succeeds, `Err(err)` if a file system error is encountered

Fs.rename

Added in 0.7.0

No other changes yet.

rename:
  (?sourceBaseDirPath: Option<Path.Path>, sourcePath: Path.Path,
   ?targetBaseDirPath: Option<Path.Path>, targetPath: Path.Path) =>
   Result<Void, FileError>

Renames a file or directory.

Parameters:

param	type	description
`?sourceBaseDirPath`	`Option<Path.Path>`	The path to the directory in which the source path resolution starts
`sourcePath`	`Path.Path`	The path of the file to rename
`?targetBaseDirPath`	`Option<Path.Path>`	The path to the directory in which the target path resolution starts
`targetPath`	`Path.Path`	The new path of the file

Returns:

type	description
`Result<Void, FileError>`	`Ok(void)` if the operation succeeds, `Err(err)` if a file system error is encountered

Fs.Binary

Functionality for reading and writing Bytes to files.

Added in 0.7.0

No other changes yet.

Values

Functions and constants included in the Fs.Binary module.

Fs.Binary.readFile

Added in 0.7.0

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readFile:
  (?sync: Bool, ?baseDirPath: Option<Path.Path>, path: Path.Path) =>
   Result<Bytes, FileError>

Read the contents of a file as Bytes.

Parameters:

param	type	description
`?sync`	`Bool`	Whether to synchronously read; `true` by default
`?baseDirPath`	`Option<Path.Path>`	The path to the directory to begin path resolution
`path`	`Path.Path`	The file path to read from

Returns:

type	description
`Result<Bytes, FileError>`	`Ok(contents)` containing the bytes read if successful or `Err(err)` if a file system error is encountered

Fs.Binary.writeFile

Added in 0.7.0

No other changes yet.

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writeFile:
  (?writeMode: WriteMode, ?sync: Bool, ?baseDirPath: Option<Path.Path>,
   path: Path.Path, data: Bytes) => Result<Void, FileError>

Write Bytes to a file.

Parameters:

param	type	description
`?writeMode`	`WriteMode`	The type of write operation to perform; `Truncate` by default
`?sync`	`Bool`	Whether to synchronously write; `true` by default
`?baseDirPath`	`Option<Path.Path>`	The path to the directory to begin path resolution
`path`	`Path.Path`	The file path to write to
`data`	`Bytes`	The bytes to write to the file

Returns:

type	description
`Result<Void, FileError>`	`Ok(void)` if the operation is successful or `Err(err)` if a file system error is encountered

Fs.Utf8

Functionality for reading and writing Strings to files.

Added in 0.7.0

No other changes yet.

Values

Functions and constants included in the Fs.Utf8 module.

Fs.Utf8.readFile

Added in 0.7.0

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readFile:
  (?sync: Bool, ?baseDirPath: Option<Path.Path>, path: Path.Path) =>
   Result<String, FileError>

Read the contents of a file as a String.

Parameters:

param	type	description
`?sync`	`Bool`	Whether to synchronously read; `true` by default
`?baseDirPath`	`Option<Path.Path>`	The path to the directory to begin path resolution
`path`	`Path.Path`	The file path to read from

Returns:

type	description
`Result<String, FileError>`	`Ok(contents)` containing the string read if successful or `Err(err)` if a file system error is encountered

Fs.Utf8.writeFile

Added in 0.7.0

No other changes yet.

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writeFile:
  (?writeMode: WriteMode, ?sync: Bool, ?baseDirPath: Option<Path.Path>,
   path: Path.Path, data: String) => Result<Void, FileError>

Write a String to a file.

Parameters:

param	type	description
`?writeMode`	`WriteMode`	The type of write operation to perform; `Truncate` by default
`?sync`	`Bool`	Whether to synchronously write; `true` by default
`?baseDirPath`	`Option<Path.Path>`	The path to the directory to begin path resolution
`path`	`Path.Path`	The file path to write to
`data`	`String`	The string to write to the file

Returns:

type	description
`Result<Void, FileError>`	`Ok(void)` if the operation is successful or `Err(err)` if a file system error is encountered