Package Exports

bitfield

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (bitfield) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

bitfield

A simple bitfield, compliant with the BitTorrent spec.

npm install bitfield

Example

import Bitfield from "bitfield";

const field = new Bitfield(256); // Create a bitfield with 256 bits.

field.set(128); // Set the 128th bit.
field.set(128, true); // Same as above.

field.get(128); // `true`
field.get(200); // `false` (all values are initialised to `false`)
field.get(1e3); // `false` (out-of-bounds is also false)

field.set(128, false); // Set the 128th bit to 0 again.

field.buffer; // The buffer used by the bitfield.

Class: BitField

Constructors

constructor

+ new BitField(data?: number | Uint8Array, opts?: BitFieldOptions): BitField

Parameters:

Name Type Default value Description

data number | Uint8Array 0 Either a number representing the maximum number of supported bytes, or a Uint8Array.

Name	Type	Default value	Description
`data`	number \| Uint8Array	0	Either a number representing the maximum number of supported bytes, or a Uint8Array.
`opts?`	{ grow: number }	{ grow: 0 }	grow: If you `set` an index that is out-of-bounds, the bitfield will automatically grow so that the bitfield is big enough to contain the given index, up to the given size (in bit). If you want the Bitfield to grow indefinitely, pass `Infinity`.

opts?

{ grow: number }

{ grow: 0 }

grow:

If you set an index that is out-of-bounds, the bitfield will automatically grow so that the bitfield is big enough to contain the given index, up to the given size (in bit).

If you want the Bitfield to grow indefinitely, pass Infinity.

Returns: BitField

Properties

buffer

• buffer: Uint8Array

The internal storage of the bitfield.

Methods

forEach

▸ forEach(fn: (bit: boolean, index: number) => void, start?: number, end?: number): void

Loop through the bits in the bitfield.

Parameters:

Name	Type	Default value	Description
`fn`	(bit: boolean, index: number) => void	-	Function to be called with the bit value and index.
`start`	number	0	Index of the first bit to look at.
`end`	number	this.buffer.length * 8	Index of the first bit that should no longer be considered.

Returns: void

get

▸ get(i: number): boolean

Get a particular bit.

Parameters:

Name	Type	Description
`i`	number	Bit index to retrieve.

Returns: boolean

A boolean indicating whether the ith bit is set.

set

▸ set(i: number, value?: boolean): void

Set a particular bit.

Will grow the underlying array if the bit is out of bounds and the grow option is set.

Parameters:

Name	Type	Default value	Description
`i`	number	-	Bit index to set.
`value`	boolean	true	Value to set the bit to. Defaults to `true`.

Returns: void

License

MIT