jsbi

library4.3.2jsnpmunverified

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.

serialization

npm install jsbi

github ↗package ↗

INSTALL

IMPORT

SIG · JSBI

jsbi

serializationjavascriptv4.3.2

Install

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Import

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Disk

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Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

JSBI

✓ import JSBI from 'jsbi';

✗ import JSBI from './jsbi.mjs';

Standard ESM import for consumers. The README's './jsbi.mjs' path is for internal use or specific bundler configurations, not the typical public API.

JSBI

✓ const JSBI = require('jsbi');

✗ const { JSBI } = require('jsbi');

Standard CommonJS import. JSBI is exported as the default, not a named export.

JSBI.BigInt

✓ import JSBI from 'jsbi'; const myBigInt = JSBI.BigInt('123');

✗ import { BigInt } from 'jsbi'; const myBigInt = BigInt('123');

BigInt is a static method of the JSBI object, not a direct named export from the package.

This example demonstrates how to import JSBI, create BigInt instances from numbers and strings, and perform arithmetic operations like addition and multiplication using JSBI's static methods, mimicking native BigInt behavior.

import JSBI from 'jsbi'; function demonstrateJSBI() { // Install: npm install jsbi const maxSafeInteger = Number.MAX_SAFE_INTEGER; console.log(`Max safe integer (JS Number): ${maxSafeInteger}`); // Create JSBI instances from numbers or strings const max = JSBI.BigInt(maxSafeInteger); console.log(`JSBI equivalent of MAX_SAFE_INTEGER: ${String(max)}`); // Use String() for clear output const other = JSBI.BigInt('2'); console.log(`Another JSBI instance: ${String(other)}`); // Perform addition using JSBI's static methods, as native operators are not overloaded const result = JSBI.add(max, other); console.log(`Result of JSBI.add(${String(max)}, ${String(other)}): ${String(result)}`); // Demonstrate arithmetic beyond Number.MAX_SAFE_INTEGER const largeNumber = JSBI.BigInt("9007199999999999"); const anotherLargeNumber = JSBI.BigInt("12345678901234567890"); const product = JSBI.multiply(largeNumber, anotherLargeNumber); console.log(`Product of two large JSBI numbers: ${String(product)}`); // Comparison operations const isGreater = JSBI.greaterThan(product, JSBI.BigInt(0)); console.log(`Is the product greater than 0? ${isGreater}`); } demonstrateJSBI();

Debug

Known issues

breakingJSBI does not polyfill native JavaScript operator overloading for BigInts (e.g., `+`, `-`, `*`, `/`). All operations must be performed using static methods provided by the `JSBI` object (e.g., `JSBI.add(a, b)`, `JSBI.multiply(a, b)`).

fix

Replace native operators with corresponding `JSBI` static methods for all BigInt arithmetic. For example, `a + b` becomes `JSBI.add(a, b)`.

affects: >=1.0.0

gotchaDirectly logging a `JSBI` instance to the console (e.g., `console.log(myJsbiInstance)`) will often display the internal object representation instead of its numeric value, which can be misleading.

fix

Always explicitly convert `JSBI` instances to a string representation before logging, using `String(myJsbiInstance)` or `myJsbiInstance.toString()`.

affects: >=1.0.0

deprecatedThe primary use case for JSBI (polyfills for BigInt) is diminishing as native BigInt support is now widespread across modern browsers (Chrome 67+, Firefox 68+, Edge 79+, Safari 14+) and Node.js (v10.4+).

fix

For new projects targeting modern environments, consider using native BigInts directly instead of JSBI. For existing projects, evaluate migration to native BigInts using `babel-plugin-transform-jsbi-to-bigint`.

affects: all

gotchaMigrating JSBI code to native BigInt syntax requires a specific Babel plugin (`babel-plugin-transform-jsbi-to-bigint`). This adds a build-step dependency and configuration complexity.

fix

Integrate `babel-plugin-transform-jsbi-to-bigint` into your Babel configuration to automatically convert JSBI syntax to native BigInts.

affects: all

Errors

Common errors & fixes

TypeError: Cannot mix BigInt and other types, use explicit conversions

Attempting to use native JavaScript operators or functions with a mix of JSBI BigInts and standard JavaScript Numbers or other primitive types.

fix

Ensure all operands in an arithmetic or comparison operation are `JSBI` instances and use `JSBI`'s static methods. If interconversion is necessary, use `JSBI.toNumber(jsbiValue)` or `JSBI.BigInt(numberValue)`.

console.log(myJsbiValue) outputs '[object Object]' or similar non-numeric representation.

The default `toString` method of the `JSBI` object returns a generic object string when implicitly converted by `console.log`.

fix

Call `String(myJsbiValue)` or `myJsbiValue.toString()` explicitly when logging `JSBI` instances to view their numeric value.

Upgrade

Version history

4.3.2latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

6 hits · last 30 days

node

Resources

githubhttps://github.com/GoogleChromeLabs/jsbi ↗

packagehttps://www.npmjs.com/package/jsbi ↗