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TTransferable
Bun

type

worker_threads.Transferable

Referenced types

class ArrayBuffer

Represents a raw buffer of binary data, which is used to store data for the different typed arrays. ArrayBuffers cannot be read from or written to directly, but can be passed to a typed array or DataView Object to interpret the raw buffer as needed.

  • readonly [Symbol.toStringTag]: string
  • readonly byteLength: number

    Read-only. The length of the ArrayBuffer (in bytes).

  • newByteLength?: number
    ): void;

    Resizes the ArrayBuffer to the specified size (in bytes).

    MDN

    byteLength: number

    Resize an ArrayBuffer in-place.

  • begin: number,
    end?: number

    Returns a section of an ArrayBuffer.

  • newByteLength?: number

    Creates a new ArrayBuffer with the same byte content as this buffer, then detaches this buffer.

    MDN

  • newByteLength?: number

    Creates a new non-resizable ArrayBuffer with the same byte content as this buffer, then detaches this buffer.

    MDN

interface MessagePort

The NodeEventTarget is a Node.js-specific extension to EventTarget that emulates a subset of the EventEmitter API.

  • onclose: null | (ev: Event) => void
  • onmessage: null | (ev: MessageEvent<any>) => void
  • onmessageerror: null | (ev: MessageEvent<any>) => void
  • type: K,
    listener: (ev: MessagePortEventMap[K]) => void,
    options?: boolean | AddEventListenerOptions
    ): void;

    Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.

    The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.

    When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.

    When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in § 2.8 Observing event listeners.

    When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.

    If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.

    The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.

    MDN Reference

    type: string,
    listener: EventListener | EventListenerObject,
    options?: boolean | AddEventListenerOptions
    ): void;

    Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.

    The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.

    When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.

    When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in § 2.8 Observing event listeners.

    When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.

    If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.

    The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.

    MDN Reference

  • event: 'close',
    listener: (ev: Event) => void
    ): this;

    Node.js-specific extension to the EventTarget class that emulates the equivalent EventEmitter API. The only difference between addListener() and addEventListener() is that addListener() will return a reference to the EventTarget.

    event: 'message',
    listener: (value: any) => void
    ): this;

    Node.js-specific extension to the EventTarget class that emulates the equivalent EventEmitter API. The only difference between addListener() and addEventListener() is that addListener() will return a reference to the EventTarget.

    event: 'messageerror',
    listener: (error: Error) => void
    ): this;

    Node.js-specific extension to the EventTarget class that emulates the equivalent EventEmitter API. The only difference between addListener() and addEventListener() is that addListener() will return a reference to the EventTarget.

    event: string,
    listener: (arg: any) => void
    ): this;

    Node.js-specific extension to the EventTarget class that emulates the equivalent EventEmitter API. The only difference between addListener() and addEventListener() is that addListener() will return a reference to the EventTarget.

  • close(): void;
  • event: Event
    ): boolean;

    Dispatches a synthetic event event to target and returns true if either event's cancelable attribute value is false or its preventDefault() method was not invoked, and false otherwise.

  • event: 'close',
    ev: Event
    ): boolean;

    Node.js-specific extension to the EventTarget class that dispatches the arg to the list of handlers for type.

    @returns

    true if event listeners registered for the type exist, otherwise false.

    event: 'message',
    value: any
    ): boolean;

    Node.js-specific extension to the EventTarget class that dispatches the arg to the list of handlers for type.

    @returns

    true if event listeners registered for the type exist, otherwise false.

    event: 'messageerror',
    error: Error
    ): boolean;

    Node.js-specific extension to the EventTarget class that dispatches the arg to the list of handlers for type.

    @returns

    true if event listeners registered for the type exist, otherwise false.

    event: string,
    arg: any
    ): boolean;

    Node.js-specific extension to the EventTarget class that dispatches the arg to the list of handlers for type.

    @returns

    true if event listeners registered for the type exist, otherwise false.

  • eventNames(): string[];

    Node.js-specific extension to the EventTarget class that returns an array of event type names for which event listeners are registered.

  • getMaxListeners(): number;

    Node.js-specific extension to the EventTarget class that returns the number of max event listeners.

  • type: string
    ): number;

    Node.js-specific extension to the EventTarget class that returns the number of event listeners registered for the type.

  • event: 'close',
    listener: (ev: Event) => void,
    options?: EventListenerOptions
    ): this;

    Node.js-specific alias for eventTarget.removeEventListener().

    event: 'message',
    listener: (value: any) => void,
    options?: EventListenerOptions
    ): this;

    Node.js-specific alias for eventTarget.removeEventListener().

    event: 'messageerror',
    listener: (error: Error) => void,
    options?: EventListenerOptions
    ): this;

    Node.js-specific alias for eventTarget.removeEventListener().

    event: string,
    listener: (arg: any) => void,
    options?: EventListenerOptions
    ): this;

    Node.js-specific alias for eventTarget.removeEventListener().

  • event: 'close',
    listener: (ev: Event) => void
    ): this;

    Node.js-specific alias for eventTarget.addEventListener().

    event: 'message',
    listener: (value: any) => void
    ): this;

    Node.js-specific alias for eventTarget.addEventListener().

    event: 'messageerror',
    listener: (error: Error) => void
    ): this;

    Node.js-specific alias for eventTarget.addEventListener().

    event: string,
    listener: (arg: any) => void
    ): this;

    Node.js-specific alias for eventTarget.addEventListener().

  • event: 'close',
    listener: (ev: Event) => void
    ): this;

    Node.js-specific extension to the EventTarget class that adds a once listener for the given event type. This is equivalent to calling on with the once option set to true.

    event: 'message',
    listener: (value: any) => void
    ): this;

    Node.js-specific extension to the EventTarget class that adds a once listener for the given event type. This is equivalent to calling on with the once option set to true.

    event: 'messageerror',
    listener: (error: Error) => void
    ): this;

    Node.js-specific extension to the EventTarget class that adds a once listener for the given event type. This is equivalent to calling on with the once option set to true.

    event: string,
    listener: (arg: any) => void
    ): this;

    Node.js-specific extension to the EventTarget class that adds a once listener for the given event type. This is equivalent to calling on with the once option set to true.

  • message: any,
    transfer: Transferable[]
    ): void;
    message: any,
    options?: StructuredSerializeOptions
    ): void;
  • type?: string
    ): this;

    Node.js-specific extension to the EventTarget class. If type is specified, removes all registered listeners for type, otherwise removes all registered listeners.

  • type: K,
    listener: (ev: MessagePortEventMap[K]) => void,
    options?: boolean | EventListenerOptions
    ): void;

    Removes the event listener in target's event listener list with the same type, callback, and options.

    MDN Reference

    type: string,
    listener: EventListener | EventListenerObject,
    options?: boolean | EventListenerOptions
    ): void;

    Removes the event listener in target's event listener list with the same type, callback, and options.

    MDN Reference

  • event: 'close',
    listener: (ev: Event) => void,
    options?: EventListenerOptions
    ): this;

    Node.js-specific extension to the EventTarget class that removes the listener for the given type. The only difference between removeListener() and removeEventListener() is that removeListener() will return a reference to the EventTarget.

    event: 'message',
    listener: (value: any) => void,
    options?: EventListenerOptions
    ): this;

    Node.js-specific extension to the EventTarget class that removes the listener for the given type. The only difference between removeListener() and removeEventListener() is that removeListener() will return a reference to the EventTarget.

    event: 'messageerror',
    listener: (error: Error) => void,
    options?: EventListenerOptions
    ): this;

    Node.js-specific extension to the EventTarget class that removes the listener for the given type. The only difference between removeListener() and removeEventListener() is that removeListener() will return a reference to the EventTarget.

    event: string,
    listener: (arg: any) => void,
    options?: EventListenerOptions
    ): this;

    Node.js-specific extension to the EventTarget class that removes the listener for the given type. The only difference between removeListener() and removeEventListener() is that removeListener() will return a reference to the EventTarget.

  • n: number
    ): void;

    Node.js-specific extension to the EventTarget class that sets the number of max event listeners as n.

  • start(): void;

class AbortSignal

A signal object that allows you to communicate with a DOM request (such as a Fetch) and abort it if required via an AbortController object.

MDN Reference

  • readonly aborted: boolean

    Returns true if this AbortSignal's AbortController has signaled to abort, and false otherwise.

    MDN Reference

  • onabort: null | (this: AbortSignal, ev: Event) => any
  • readonly reason: any
  • addEventListener<K extends 'abort'>(
    type: K,
    listener: (this: AbortSignal, ev: AbortSignalEventMap[K]) => any,
    options?: boolean | AddEventListenerOptions
    ): void;

    Appends an event listener for events whose type attribute value is type. The callback argument sets the callback that will be invoked when the event is dispatched.

    The options argument sets listener-specific options. For compatibility this can be a boolean, in which case the method behaves exactly as if the value was specified as options's capture.

    When set to true, options's capture prevents callback from being invoked when the event's eventPhase attribute value is BUBBLING_PHASE. When false (or not present), callback will not be invoked when event's eventPhase attribute value is CAPTURING_PHASE. Either way, callback will be invoked if event's eventPhase attribute value is AT_TARGET.

    When set to true, options's passive indicates that the callback will not cancel the event by invoking preventDefault(). This is used to enable performance optimizations described in § 2.8 Observing event listeners.

    When set to true, options's once indicates that the callback will only be invoked once after which the event listener will be removed.

    If an AbortSignal is passed for options's signal, then the event listener will be removed when signal is aborted.

    The event listener is appended to target's event listener list and is not appended if it has the same type, callback, and capture.

    MDN Reference

  • event: Event
    ): boolean;

    Dispatches a synthetic event event to target and returns true if either event's cancelable attribute value is false or its preventDefault() method was not invoked, and false otherwise.

  • removeEventListener<K extends 'abort'>(
    type: K,
    listener: (this: AbortSignal, ev: AbortSignalEventMap[K]) => any,
    options?: boolean | EventListenerOptions
    ): void;

    Removes the event listener in target's event listener list with the same type, callback, and options.

    MDN Reference

  • static abort(
    reason?: any
  • static timeout(
    milliseconds: number

interface FileHandle

  • readonly fd: number

    The numeric file descriptor managed by the {FileHandle} object.

  • [Symbol.asyncDispose](): Promise<void>;

    Calls filehandle.close() and returns a promise that fulfills when the filehandle is closed.

  • data: string | Uint8Array<ArrayBufferLike>,
    options?: null | BufferEncoding | ObjectEncodingOptions & Abortable
    ): Promise<void>;

    Alias of filehandle.writeFile().

    When operating on file handles, the mode cannot be changed from what it was set to with fsPromises.open(). Therefore, this is equivalent to filehandle.writeFile().

    @returns

    Fulfills with undefined upon success.

  • mode: Mode
    ): Promise<void>;

    Modifies the permissions on the file. See chmod(2).

    @param mode

    the file mode bit mask.

    @returns

    Fulfills with undefined upon success.

  • uid: number,
    gid: number
    ): Promise<void>;

    Changes the ownership of the file. A wrapper for chown(2).

    @param uid

    The file's new owner's user id.

    @param gid

    The file's new group's group id.

    @returns

    Fulfills with undefined upon success.

  • close(): Promise<void>;

    Closes the file handle after waiting for any pending operation on the handle to complete.

    import { open } from 'node:fs/promises';

let filehandle;
try {
  filehandle = await open('thefile.txt', 'r');
} finally {
  await filehandle?.close();
}
    @returns

    Fulfills with undefined upon success.

  • options?: CreateReadStreamOptions

    Unlike the 16 KiB default highWaterMark for a stream.Readable, the stream returned by this method has a default highWaterMark of 64 KiB.

    options can include start and end values to read a range of bytes from the file instead of the entire file. Both start and end are inclusive and start counting at 0, allowed values are in the [0, Number.MAX_SAFE_INTEGER] range. If start is omitted or undefined, filehandle.createReadStream() reads sequentially from the current file position. The encoding can be any one of those accepted by Buffer.

    If the FileHandle points to a character device that only supports blocking reads (such as keyboard or sound card), read operations do not finish until data is available. This can prevent the process from exiting and the stream from closing naturally.

    By default, the stream will emit a 'close' event after it has been destroyed. Set the emitClose option to false to change this behavior.

    import { open } from 'node:fs/promises';

const fd = await open('/dev/input/event0');
// Create a stream from some character device.
const stream = fd.createReadStream();
setTimeout(() => {
  stream.close(); // This may not close the stream.
  // Artificially marking end-of-stream, as if the underlying resource had
  // indicated end-of-file by itself, allows the stream to close.
  // This does not cancel pending read operations, and if there is such an
  // operation, the process may still not be able to exit successfully
  // until it finishes.
  stream.push(null);
  stream.read(0);
}, 100);

    If autoClose is false, then the file descriptor won't be closed, even if there's an error. It is the application's responsibility to close it and make sure there's no file descriptor leak. If autoClose is set to true (default behavior), on 'error' or 'end' the file descriptor will be closed automatically.

    An example to read the last 10 bytes of a file which is 100 bytes long:

    import { open } from 'node:fs/promises';

const fd = await open('sample.txt');
fd.createReadStream({ start: 90, end: 99 });
  • options?: CreateWriteStreamOptions

    options may also include a start option to allow writing data at some position past the beginning of the file, allowed values are in the [0, Number.MAX_SAFE_INTEGER] range. Modifying a file rather than replacing it may require the flags open option to be set to r+ rather than the default r. The encoding can be any one of those accepted by Buffer.

    If autoClose is set to true (default behavior) on 'error' or 'finish' the file descriptor will be closed automatically. If autoClose is false, then the file descriptor won't be closed, even if there's an error. It is the application's responsibility to close it and make sure there's no file descriptor leak.

    By default, the stream will emit a 'close' event after it has been destroyed. Set the emitClose option to false to change this behavior.

  • datasync(): Promise<void>;

    Forces all currently queued I/O operations associated with the file to the operating system's synchronized I/O completion state. Refer to the POSIX fdatasync(2) documentation for details.

    Unlike filehandle.sync this method does not flush modified metadata.

    @returns

    Fulfills with undefined upon success.

  • read<T extends ArrayBufferView<ArrayBufferLike>>(
    buffer: T,
    offset?: null | number,
    length?: null | number,
    position?: null | ReadPosition
    ): Promise<FileReadResult<T>>;

    Reads data from the file and stores that in the given buffer.

    If the file is not modified concurrently, the end-of-file is reached when the number of bytes read is zero.

    @param buffer

    A buffer that will be filled with the file data read.

    @param offset

    The location in the buffer at which to start filling.

    @param length

    The number of bytes to read.

    @param position

    The location where to begin reading data from the file. If null, data will be read from the current file position, and the position will be updated. If position is an integer, the current file position will remain unchanged.

    @returns

    Fulfills upon success with an object with two properties:

    read<T extends ArrayBufferView<ArrayBufferLike>>(
    buffer: T,
    options?: ReadOptions
    ): Promise<FileReadResult<T>>;
    read<T extends ArrayBufferView<ArrayBufferLike> = NonSharedBuffer>(
    options?: ReadOptionsWithBuffer<T>
    ): Promise<FileReadResult<T>>;
  • options?: ReadableWebStreamOptions

    Returns a byte-oriented ReadableStream that may be used to read the file's contents.

    An error will be thrown if this method is called more than once or is called after the FileHandle is closed or closing.

    import {
  open,
} from 'node:fs/promises';

const file = await open('./some/file/to/read');

for await (const chunk of file.readableWebStream())
  console.log(chunk);

await file.close();

    While the ReadableStream will read the file to completion, it will not close the FileHandle automatically. User code must still call thefileHandle.close() method.

  • options?: null | { encoding: null } & Abortable
    ): Promise<NonSharedBuffer>;

    Asynchronously reads the entire contents of a file.

    If options is a string, then it specifies the encoding.

    The FileHandle has to support reading.

    If one or more filehandle.read() calls are made on a file handle and then a filehandle.readFile() call is made, the data will be read from the current position till the end of the file. It doesn't always read from the beginning of the file.

    @returns

    Fulfills upon a successful read with the contents of the file. If no encoding is specified (using options.encoding), the data is returned as a {Buffer} object. Otherwise, the data will be a string.

    options: BufferEncoding | { encoding: BufferEncoding } & Abortable
    ): Promise<string>;

    Asynchronously reads the entire contents of a file. The underlying file will not be closed automatically. The FileHandle must have been opened for reading.

    options?: null | BufferEncoding | ObjectEncodingOptions & Abortable
    ): Promise<string | NonSharedBuffer>;

    Asynchronously reads the entire contents of a file. The underlying file will not be closed automatically. The FileHandle must have been opened for reading.

  • options?: CreateReadStreamOptions

    Convenience method to create a readline interface and stream over the file. See filehandle.createReadStream() for the options.

    import { open } from 'node:fs/promises';

const file = await open('./some/file/to/read');

for await (const line of file.readLines()) {
  console.log(line);
}
  • readv<TBuffers extends readonly ArrayBufferView<ArrayBufferLike>[]>(
    buffers: TBuffers,
    position?: number
    ): Promise<ReadVResult<TBuffers>>;
    @param position

    The offset from the beginning of the file where the data should be read from. If position is not a number, the data will be read from the current position.

    @returns

    Fulfills upon success an object containing two properties:

  • opts?: StatOptions & { bigint: false }
    ): Promise<Stats>;
    @returns

    Fulfills with an {fs.Stats} for the file.

    opts: StatOptions & { bigint: true }
    ): Promise<BigIntStats>;
    opts?: StatOptions
    ): Promise<Stats | BigIntStats>;
  • sync(): Promise<void>;

    Request that all data for the open file descriptor is flushed to the storage device. The specific implementation is operating system and device specific. Refer to the POSIX fsync(2) documentation for more detail.

    @returns

    Fulfills with undefined upon success.

  • len?: number
    ): Promise<void>;

    Truncates the file.

    If the file was larger than len bytes, only the first len bytes will be retained in the file.

    The following example retains only the first four bytes of the file:

    import { open } from 'node:fs/promises';

let filehandle = null;
try {
  filehandle = await open('temp.txt', 'r+');
  await filehandle.truncate(4);
} finally {
  await filehandle?.close();
}

    If the file previously was shorter than len bytes, it is extended, and the extended part is filled with null bytes ('\0'):

    If len is negative then 0 will be used.

    @returns

    Fulfills with undefined upon success.

  • atime: TimeLike,
    mtime: TimeLike
    ): Promise<void>;

    Change the file system timestamps of the object referenced by the FileHandle then fulfills the promise with no arguments upon success.

  • write<TBuffer extends ArrayBufferView<ArrayBufferLike>>(
    buffer: TBuffer,
    offset?: null | number,
    length?: null | number,
    position?: null | number
    ): Promise<{ buffer: TBuffer; bytesWritten: number }>;

    Write buffer to the file.

    The promise is fulfilled with an object containing two properties:

    It is unsafe to use filehandle.write() multiple times on the same file without waiting for the promise to be fulfilled (or rejected). For this scenario, use filehandle.createWriteStream().

    On Linux, positional writes do not work when the file is opened in append mode. The kernel ignores the position argument and always appends the data to the end of the file.

    @param offset

    The start position from within buffer where the data to write begins.

    @param length

    The number of bytes from buffer to write.

    @param position

    The offset from the beginning of the file where the data from buffer should be written. If position is not a number, the data will be written at the current position. See the POSIX pwrite(2) documentation for more detail.

    write<TBuffer extends Uint8Array<ArrayBufferLike>>(
    buffer: TBuffer,
    options?: { length: number; offset: number; position: number }
    ): Promise<{ buffer: TBuffer; bytesWritten: number }>;
    data: string,
    position?: null | number,
    encoding?: null | BufferEncoding
    ): Promise<{ buffer: string; bytesWritten: number }>;
  • data: string | Uint8Array<ArrayBufferLike>,
    options?: null | BufferEncoding | ObjectEncodingOptions & Abortable
    ): Promise<void>;

    Asynchronously writes data to a file, replacing the file if it already exists. data can be a string, a buffer, an AsyncIterable, or an Iterable object. The promise is fulfilled with no arguments upon success.

    If options is a string, then it specifies the encoding.

    The FileHandle has to support writing.

    It is unsafe to use filehandle.writeFile() multiple times on the same file without waiting for the promise to be fulfilled (or rejected).

    If one or more filehandle.write() calls are made on a file handle and then afilehandle.writeFile() call is made, the data will be written from the current position till the end of the file. It doesn't always write from the beginning of the file.

  • writev<TBuffers extends readonly ArrayBufferView<ArrayBufferLike>[]>(
    buffers: TBuffers,
    position?: number
    ): Promise<WriteVResult<TBuffers>>;

    Write an array of ArrayBufferView s to the file.

    The promise is fulfilled with an object containing a two properties:

    It is unsafe to call writev() multiple times on the same file without waiting for the promise to be fulfilled (or rejected).

    On Linux, positional writes don't work when the file is opened in append mode. The kernel ignores the position argument and always appends the data to the end of the file.

    @param position

    The offset from the beginning of the file where the data from buffers should be written. If position is not a number, the data will be written at the current position.

interface ReadableStream<R = any>

interface WritableStream<W = any>

interface TransformStream<I = any, O = any>