§Namespaces

Deno
Deno.errors

A set of error constructors that are raised by Deno APIs.

§Classes

Deno.Buffer deprecated
Deno.errors.AddrInUse
Deno.errors.AddrNotAvailable
Deno.errors.AlreadyExists
Deno.errors.BadResource
Deno.errors.BrokenPipe
Deno.errors.Busy
Deno.errors.ConnectionAborted
Deno.errors.ConnectionRefused
Deno.errors.ConnectionReset
Deno.errors.Http
Deno.errors.Interrupted
Deno.errors.InvalidData
Deno.errors.NotConnected
Deno.errors.NotFound
Deno.errors.NotSupported
Deno.errors.PermissionDenied
Deno.errors.TimedOut
Deno.errors.UnexpectedEof
Deno.errors.WriteZero
Deno.File deprecated
Deno.FsFile

The Deno abstraction for reading and writing files.

Deno.Permissions
Deno.PermissionStatus
Deno.Process

§Enums

Deno.SeekMode

§Variables

Deno.args

Returns the script arguments to the program. If for example we run a program:

Deno.build

Build related information.

Deno.customInspect deprecated

A symbol which can be used as a key for a custom method which will be called when Deno.inspect() is called, or when the object is logged to the console.

Deno.env
Deno.mainModule

The URL of the entrypoint module entered from the command-line.

Deno.noColor

Reflects the NO_COLOR environment variable at program start.

Deno.permissions

Deno's permission management API.

Deno.pid

The current process id of the runtime.

Deno.ppid

The pid of the current process's parent.

Deno.stderr

A handle for stderr.

Deno.stdin

A handle for stdin.

Deno.stdout

A handle for stdout.

Deno.version

Version related information.

§Functions

Deno.addSignalListener

Registers the given function as a listener of the given signal event.

Deno.chdir

Change the current working directory to the specified path.

Deno.chmod

Changes the permission of a specific file/directory of specified path. Ignores the process's umask.

Deno.chmodSync

Synchronously changes the permission of a specific file/directory of specified path. Ignores the process's umask.

Deno.chown

Change owner of a regular file or directory. This functionality is not available on Windows.

Deno.chownSync

Synchronously change owner of a regular file or directory. This functionality is not available on Windows.

Deno.close

Close the given resource ID (rid) which has been previously opened, such as via opening or creating a file. Closing a file when you are finished with it is important to avoid leaking resources.

Deno.copy deprecated

Copies from src to dst until either EOF (null) is read from src or an error occurs. It resolves to the number of bytes copied or rejects with the first error encountered while copying.

Deno.copyFile

Copies the contents and permissions of one file to another specified path, by default creating a new file if needed, else overwriting. Fails if target path is a directory or is unwritable.

Deno.copyFileSync

Synchronously copies the contents and permissions of one file to another specified path, by default creating a new file if needed, else overwriting. Fails if target path is a directory or is unwritable.

Deno.create

Creates a file if none exists or truncates an existing file and resolves to an instance of Deno.FsFile.

Deno.createSync

Creates a file if none exists or truncates an existing file and returns an instance of Deno.FsFile.

Deno.cwd

Return a string representing the current working directory.

Deno.execPath

Returns the path to the current deno executable.

Deno.exit

Exit the Deno process with optional exit code. If no exit code is supplied then Deno will exit with return code of 0.

Deno.fdatasync

Flushes any pending data operations of the given file stream to disk.

const file = await Deno.open("my_file.txt", { read: true, write: true, create: true });
await Deno.write(file.rid, new TextEncoder().encode("Hello World"));
await Deno.fdatasync(file.rid);
console.log(new TextDecoder().decode(await Deno.readFile("my_file.txt"))); // Hello World
Deno.fdatasyncSync
Deno.fstat

Returns a Deno.FileInfo for the given file stream.

Deno.fstatSync

Synchronously returns a Deno.FileInfo for the given file stream.

Deno.fsync

Flushes any pending data and metadata operations of the given file stream to disk.

const file = await Deno.open("my_file.txt", { read: true, write: true, create: true });
await Deno.write(file.rid, new TextEncoder().encode("Hello World"));
await Deno.ftruncate(file.rid, 1);
await Deno.fsync(file.rid);
console.log(new TextDecoder().decode(await Deno.readFile("my_file.txt"))); // H
Deno.fsyncSync

Synchronously flushes any pending data and metadata operations of the given file stream to disk.

const file = Deno.openSync("my_file.txt", { read: true, write: true, create: true });
Deno.writeSync(file.rid, new TextEncoder().encode("Hello World"));
Deno.ftruncateSync(file.rid, 1);
Deno.fsyncSync(file.rid);
console.log(new TextDecoder().decode(Deno.readFileSync("my_file.txt"))); // H
Deno.ftruncate

Truncates or extends the specified file stream, to reach the specified len.

Deno.ftruncateSync

Synchronously truncates or extends the specified file stream, to reach the specified len.

Deno.inspect

Converts the input into a string that has the same format as printed by console.log().

Deno.isatty

Check if a given resource id (rid) is a TTY.

Deno.iter deprecated

Turns a Reader, r, into an async iterator.

Deno.iterSync deprecated

Turns a ReaderSync, r, into an iterator.

Deno.kill

Send a signal to process under given pid.

Deno.link

Creates newpath as a hard link to oldpath.

Deno.linkSync

Synchronously creates newpath as a hard link to oldpath.

Deno.lstat

Resolves to a Deno.FileInfo for the specified path. If path is a symlink, information for the symlink will be returned instead of what it points to.

Deno.lstatSync

Synchronously returns a Deno.FileInfo for the specified path. If path is a symlink, information for the symlink will be returned instead of what it points to..

Deno.makeTempDir

Creates a new temporary directory in the default directory for temporary files, unless dir is specified. Other optional options include prefixing and suffixing the directory name with prefix and suffix respectively.

Deno.makeTempDirSync

Synchronously creates a new temporary directory in the default directory for temporary files, unless dir is specified. Other optional options include prefixing and suffixing the directory name with prefix and suffix respectively.

Deno.makeTempFile

Creates a new temporary file in the default directory for temporary files, unless dir is specified. Other optional options include prefixing and suffixing the directory name with prefix and suffix respectively.

Deno.makeTempFileSync

Synchronously creates a new temporary file in the default directory for temporary files, unless dir is specified. Other optional options include prefixing and suffixing the directory name with prefix and suffix respectively.

Deno.memoryUsage

Returns an object describing the memory usage of the Deno process measured in bytes.

Deno.metrics

Receive metrics from the privileged side of Deno. This is primarily used in the development of Deno. 'Ops', also called 'bindings', are the go-between between Deno JavaScript and Deno Rust.

Deno.mkdir

Creates a new directory with the specified path.

Deno.mkdirSync

Synchronously creates a new directory with the specified path.

Deno.open

Open a file and resolve to an instance of Deno.FsFile. The file does not need to previously exist if using the create or createNew open options. It is the callers responsibility to close the file when finished with it.

Deno.openSync

Synchronously open a file and return an instance of Deno.FsFile. The file does not need to previously exist if using the create or createNew open options. It is the callers responsibility to close the file when finished with it.

Deno.read

Read from a resource ID (rid) into an array buffer (buffer).

Deno.readAll deprecated

Read Reader r until EOF (null) and resolve to the content as Uint8Array`.

Deno.readAllSync deprecated

Synchronously reads Reader r until EOF (null) and returns the content as Uint8Array.

Deno.readDir

Reads the directory given by path and returns an async iterable of Deno.DirEntry.

Deno.readDirSync

Synchronously reads the directory given by path and returns an iterable of Deno.DirEntry.

Deno.readFile

Reads and resolves to the entire contents of a file as an array of bytes. TextDecoder can be used to transform the bytes to string if required. Reading a directory returns an empty data array.

Deno.readFileSync

Synchronously reads and returns the entire contents of a file as an array of bytes. TextDecoder can be used to transform the bytes to string if required. Reading a directory returns an empty data array.

Deno.readLink

Resolves to the full path destination of the named symbolic link.

Deno.readLinkSync

Returns the full path destination of the named symbolic link.

Deno.readSync

Synchronously read from a resource ID (rid) into an array buffer (buffer).

Deno.readTextFile

Asynchronously reads and returns the entire contents of a file as utf8 encoded string. Reading a directory throws an error.

Deno.readTextFileSync

Synchronously reads and returns the entire contents of a file as utf8 encoded string. Reading a directory throws an error.

Deno.realPath

Resolves to the absolute normalized path, with symbolic links resolved.

Deno.realPathSync

Returns absolute normalized path, with symbolic links resolved.

Deno.remove

Removes the named file or directory.

Deno.removeSignalListener

Removes the given signal listener that has been registered with Deno.addSignalListener.

Deno.removeSync

Synchronously removes the named file or directory.

Deno.rename

Renames (moves) oldpath to newpath. Paths may be files or directories. If newpath already exists and is not a directory, rename() replaces it. OS-specific restrictions may apply when oldpath and newpath are in different directories.

Deno.renameSync

Synchronously renames (moves) oldpath to newpath. Paths may be files or directories. If newpath already exists and is not a directory, renameSync() replaces it. OS-specific restrictions may apply when oldpath and newpath are in different directories.

Deno.resolveDns
Deno.resources

Returns a map of open resource ids (rid) along with their string representations. This is an internal API and as such resource representation has any type; that means it can change any time.

Deno.run

Spawns new subprocess. RunOptions must contain at a minimum the opt.cmd, an array of program arguments, the first of which is the binary.

Deno.seek

Seek a resource ID (rid) to the given offset under mode given by whence. The call resolves to the new position within the resource (bytes from the start).

Deno.seekSync

Synchronously seek a resource ID (rid) to the given offset under mode given by whence. The new position within the resource (bytes from the start) is returned.

Deno.serveHttp

Services HTTP requests given a TCP or TLS socket.

Deno.stat

Resolves to a Deno.FileInfo for the specified path. Will always follow symlinks.

Deno.statSync

Synchronously returns a Deno.FileInfo for the specified path. Will always follow symlinks.

Deno.symlink

Creates newpath as a symbolic link to oldpath.

Deno.symlinkSync

Creates newpath as a symbolic link to oldpath.

Deno.test

Register a test which will be run when deno test is used on the command line and the containing module looks like a test module. fn can be async if required.

import {assert, fail, assertEquals} from "https://deno.land/std/testing/asserts.ts";
Deno.truncate

Truncates or extends the specified file, to reach the specified len. If len is not specified then the entire file contents are truncated.

Deno.truncateSync

Synchronously truncates or extends the specified file, to reach the specified len. If len is not specified then the entire file contents are truncated.

Deno.upgradeWebSocket

Used to upgrade an incoming HTTP request to a WebSocket.

Deno.watchFs

Watch for file system events against one or more paths, which can be files or directories. These paths must exist already. One user action (e.g. touch test.file) can generate multiple file system events. Likewise, one user action can result in multiple file paths in one event (e.g. mv old_name.txt new_name.txt). Recursive option is true by default and, for directories, will watch the specified directory and all sub directories. Note that the exact ordering of the events can vary between operating systems.

Deno.write

Write to the resource ID (rid) the contents of the array buffer (data).

Deno.writeAll deprecated

Write all the content of the array buffer (arr) to the writer (w).

Deno.writeAllSync deprecated

Synchronously write all the content of the array buffer (arr) to the writer (w).

Deno.writeFile

Write data to the given path, by default creating a new file if needed, else overwriting.

Deno.writeFileSync

Synchronously write data to the given path, by default creating a new file if needed, else overwriting.

Deno.writeSync

Synchronously write to the resource ID (rid) the contents of the array buffer (data).

Deno.writeTextFile

Asynchronously write string data to the given path, by default creating a new file if needed, else overwriting.

Deno.writeTextFileSync

Synchronously write string data to the given path, by default creating a new file if needed, else overwriting.

§Interfaces

Deno.CAARecord

If resolveDns is called with "CAA" record type specified, it will return an array of this interface.

Deno.Closer
Deno.DirEntry
Deno.EnvPermissionDescriptor
Deno.FfiPermissionDescriptor
Deno.FileInfo

A FileInfo describes a file and is returned by stat, lstat, statSync, lstatSync.

Deno.FsEvent
Deno.FsWatcher

FsWatcher is returned by Deno.watchFs function when you start watching the file system. You can iterate over this interface to get the file system events, and also you can stop watching the file system by calling .close() method.

Deno.HrtimePermissionDescriptor
Deno.HttpConn
Deno.InspectOptions
Deno.MakeTempOptions
Deno.MemoryUsage
Deno.Metrics
Deno.MkdirOptions
Deno.MXRecord

If resolveDns is called with "MX" record type specified, it will return an array of this interface.

Deno.NAPTRRecord

If resolveDns is called with "NAPTR" record type specified, it will return an array of this interface.

Deno.NetPermissionDescriptor
Deno.OpenOptions
Deno.OpMetrics
Deno.PermissionOptionsObject
Deno.PermissionStatusEventMap
Deno.Reader
Deno.ReaderSync
Deno.ReadFileOptions
Deno.ReadPermissionDescriptor
Deno.RemoveOptions
Deno.RequestEvent
Deno.ResolveDnsOptions
Deno.RunOptions
Deno.RunPermissionDescriptor
Deno.Seeker
Deno.SeekerSync
Deno.SOARecord

If resolveDns is called with "SOA" record type specified, it will return an array of this interface.

Deno.SRVRecord

If resolveDns is called with "SRV" record type specified, it will return an array of this interface.

Deno.TestContext
Deno.TestDefinition
Deno.TestStepDefinition
Deno.UpgradeWebSocketOptions
Deno.WebSocketUpgrade
Deno.WriteFileOptions

Options for writing to a file.

Deno.WritePermissionDescriptor
Deno.Writer
Deno.WriterSync
ImportMeta

Deno provides extra properties on import.meta. These are included here to ensure that these are still available when using the Deno namespace in conjunction with other type libs, like dom.

Performance

Deno supports user timing Level 3 (see: https://w3c.github.io/user-timing) which is not widely supported yet in other runtimes. These types are here so that these features are still available when using the Deno namespace in conjunction with other type libs, like dom.

PerformanceMarkOptions
PerformanceMeasureOptions

§Type Aliases

Deno.FsEventFlag

Additional information for FsEvent objects with the "other" kind.

Deno.PermissionDescriptor

Permission descriptors which define a permission and can be queried, requested, or revoked.

Deno.PermissionName

The name of a "powerful feature" which needs permission.

Deno.PermissionOptions
Deno.PermissionState

The current status of the permission.

Deno.ProcessStatus
Deno.RecordType

The type of the resource record. Only the listed types are supported currently.

Deno.Signal
Deno.SymlinkOptions