extra-bit

A collection of common bitwise operations.
📦 Node.js, 🌐 Web, 📜 Files, 📰 Docs, 📘 Wiki.

The bit is a basic unit of information in information theory, computing. This package includes bit twiddling hacks by Sean Eron Anderson and many others. JavaScript converts a Number (a 64-bit floating point number) to a 32-bit integer when bitwise operators (such as |) are applied. All bitwise operations are performed on 32-bit integers.

This package is available in Node.js and Web formats. The web format is exposed as extra_bit standalone variable and can be loaded from jsDelivr CDN.

Stability: Experimental.

const bit = require('extra-bit');
// import * as bit from "extra-bit";
// import * as bit from "https://unpkg.com/extra-bit/index.mjs"; (deno)

bit.count(7);
// → 3 (111 ⇒ 3)

bit.parity(8, 2);
// → 2 (10,00 ⇒ 10)

bit.swap(6, 1, 0);
// → 5 (110 ⇒ 101)

bit.reverse(0xFFFF0000);
// → 65535 (0x0000FFFF)

bit.signExtend(15, 4);
// → -1

Index

Property	Description
get	Get bits at specified index.
getAs	Get bits as per mask.
set	Set bits at specified index.
setAs	Set bits as per mask.
toggle	Toggle bits at specified index.
toggleAs	Toggle bits as per mask.
swap	Swap bit sequences at specified indices.
scan	Find index of first set bit from LSB.
scanReverse	Find index of first set bit from MSB.
count	Count bits set.
parity	Calculate n-bit parity.
rotate	Rotate bits by a certain amount.
reverse	Reverse all bits.
merge	Merge bits as per mask.
interleave	Interleave bits of two int16s.
signExtend	Sign extend variable bit-width integer.

References

• Bit Twiddling Hacks by Sean Eron Anderson
• bit-twiddle package by @mikolalysenko