JSBI: Pure JavaScript BigInt Implementation

JSBI (JavaScript BigInt) is a pure-JavaScript implementation of the ECMAScript BigInt proposal, which officially became a part of the JavaScript language in ES2020. The current stable version is 4.3.2. This library serves as a robust polyfill, enabling developers to use arbitrary-precision integers in JavaScript environments that lack native BigInt support, such as older browsers and Node.js versions. A key differentiator of JSBI is its precise adherence to the native BigInt specification's behavior, which facilitates a straightforward, mechanical migration path to native BigInts once they are universally supported, often accomplished through the `babel-plugin-transform-jsbi-to-bigint` plugin. JSBI prioritizes performance, aiming to be highly competitive with native BigInt implementations. Its release cadence is primarily driven by maintenance requirements and alignment with ECMAScript specification updates, rather than frequent feature additions, given its role as a specification-compliant polyfill.