fix: handle BigInt values in JSON type serializer

[claygeo]

Problem

When arrays or objects containing BigInt values are passed as JSON/JSONB parameters, the JSON serializer throws:

TypeError: Do not know how to serialize a BigInt

Reproduction:

const pg = new PGlite();
await pg.exec(`CREATE TABLE test (id BIGINT, name TEXT)`);

// This throws:
await pg.query(
  `INSERT INTO test SELECT * FROM json_to_recordset($1) AS x(id BIGINT, name TEXT)`,
  [JSON.stringify([{ id: 1n, name: 'a' }, { id: 2n, name: 'b' }])]
);

The standalone bigint type handler (OID 20) correctly serializes BigInt via .toString(), but when BigInt values are nested inside JSON/JSONB parameters (OID 114/3802), the JSON serializer at types.ts:115 calls native JSON.stringify which has no BigInt support.

This particularly affects pglite-sync's JSON initial insert mode, which uses json_to_recordset for bulk inserts and BigInt for LSN tracking.

Solution

Add a replacer function to JSON.stringify in the JSON type serializer that converts BigInt values to their string representation. This matches the behavior of the standalone bigint type handler and is consistent with the common BigInt.prototype.toJSON workaround.

return JSON_stringify(x, (_key: string, value: unknown) =>
  typeof value === 'bigint' ? value.toString() : value,
)

Changes

• packages/pglite/src/types.ts — Added BigInt replacer to JSON type serializer

Test Plan

• pg.query('SELECT $1::json', [{ id: 1n }]) — no longer throws
• pg.query('SELECT $1::json', [{ id: 1 }]) — existing behavior preserved (numbers unchanged)
• pg.query('SELECT $1::json', ['{"id": 1}']) — string passthrough unchanged
• pg.query('SELECT $1::int8', [1n]) — standalone bigint handler still works

Closes #899

[tdrz]

@claygeo Thank you for this!

Could you please add the tests in your 'Test Plan' to packages/pglite/tests/types.test.ts?

[claygeo]

Added the tests to packages/pglite/tests/types.test.ts — covers all four cases from the test plan:

• BigInt nested in a JSON object → serializes to string without throwing
• BigInt nested in an array of objects → same
• JSONB serializer (OID 3802) handles BigInt identically to JSON (OID 114)
• Regular number values are preserved as numbers (regression guard)
• Pre-serialized string passthrough is unchanged

Let me know if you'd like any changes!

[tdrz]

Why did you remove this?