@bybrave/json5

Maintained, drop-in fork of json5 — the JSON5 (JSON for humans) parser and stringifier: comments, unquoted keys, trailing commas, single quotes, hex, and more.

The original has had no release since 2022 (2.2.3) while still pulling ~800M downloads/month. This fork keeps the parser 100% compatible and fixes the long-standing ESM packaging bug, modernizes the build, and bundles TypeScript types.

npm install @bybrave/json5

const JSON5 = require('@bybrave/json5');        // CommonJS
import JSON5 from '@bybrave/json5';              // ESM (default)
import { parse, stringify } from '@bybrave/json5'; // ESM (named) — now works

Same API as json5: JSON5.parse(text, reviver?) and JSON5.stringify(value, replacer?, space?).

What's fixed

| Issue | Problem | Fix | |---|---|---| | #240 | The ESM build (module field) exported only { default: {...} } while CJS exported { parse, stringify }. Bundlers that prefer module (webpack) broke on import { parse }, and import/require disagreed on shape. | ESM-first sources with an exports map: import JSON5 from …, import { parse, stringify } from …, and require(…) all resolve to the same shape. | | #348 | Request to ship real ES modules (tree-shaking, no CJS-interop shim). | Sources are ES modules; the CJS entry is generated from them via the require condition. | | #205 | Ask to drop the minimist CLI dependency. | Already resolved upstream (CLI uses a hand-rolled arg parser); this fork ships zero runtime dependencies. |

Modernized build

The original toolchain (rollup 0.64 + buble + core-js 2, 15 dev-dependencies) is replaced by a single esbuild step producing the CJS entry and a minified browser (UMD-style window.JSON5) bundle. Dev-dependencies drop to three (esbuild, typescript, @types/node). No runtime dependencies.

Targets Node 18+. The browser bundle targets ES2015 (the original ES5 legacy target is dropped — a deliberate choice for a 2026 major).

Extras (opt-in)

Large integers (bigint) — integer literals outside the safe range lose precision in JSON.parse/json5. Pass { bigint: true } to get them back as BigInt (#292); everything else is unchanged, and stringify serializes BigInt back to a bare literal:

JSON5.parse('12345678901234567890');                 // 12345678901234567000  (imprecise)
JSON5.parse('12345678901234567890', { bigint: true }); // 12345678901234567890n
JSON5.stringify(99999999999999999999n);               // '99999999999999999999'

Options may also be passed as the second argument: JSON5.parse(text, { bigint: true }).

Lone surrogates — stringify now escapes unpaired surrogate code units as \uXXXX instead of emitting an invalid string that reads back as U+FFFD (#192). Valid surrogate pairs (emoji, etc.) are untouched.

Migration from json5

Replace the dependency and the import — the parser and stringifier behave identically. The only change is packaging: import { parse, stringify } now works, and the import/require shapes match. If you consumed the deprecated json5/register require-hook, it moved to @bybrave/json5/register.

Support

If this package saves you time, you can support maintenance:

Bitcoin (BTC): bc1q37557q5jpeaxqydzwvf3jgj7zhnfpn2td3q40q

Credits & license

MIT, same as the original — see LICENSE.md. Based on json5 by Aseem Kishore, Jordan Tucker and contributors.