Problem with inserting big numbers (more than 64bit)

Consider the following PostgreSQL table:

CREATE TABLE scratchpad (
	n NUMERIC(78, 0)
)

I can run this query without any problem:

INSERT INTO scratchpad
VALUES (57896044618658097711785492504343953926634992332820282019728792003956564819968)

Also works with

INSERT INTO scratchpad
VALUES ('57896044618658097711785492504343953926634992332820282019728792003956564819968')

Or

INSERT INTO scratchpad
VALUES (NUMERIC '57896044618658097711785492504343953926634992332820282019728792003956564819968')

but if I try this with Postgres-JS:

main.js

require('dotenv').config();
const postgres = require('postgres');

const sql = postgres({ debug: true });

async function main() {
  const bn = 1n << 255n;
  await sql`INSERT INTO scratchpad (n) VALUES (${bn})`;
}

main().catch(console.error);

$ node main.js
PostgresError: value "57896044618658097711785492504343953926634992332820282019728792003956564819968" is out of range for type bigint
    at ErrorResponse (/app/node_modules/postgres/cjs/src/connection.js:788:26)
    at handle (/app/node_modules/postgres/cjs/src/connection.js:474:6)
    at Socket.data (/app/node_modules/postgres/cjs/src/connection.js:315:9)
    at Socket.emit (node:events:519:28)
    at addChunk (node:internal/streams/readable:559:12)
    at readableAddChunkPushByteMode (node:internal/streams/readable:510:3)
    at Readable.push (node:internal/streams/readable:390:5)
    at TCP.onStreamRead (node:internal/stream_base_commons:191:23)
    at new Query (/app/node_modules/postgres/cjs/src/query.js:35:9)
    at sql (/app/node_modules/postgres/cjs/src/index.js:112:11)
    at main (/app/main.js:10:12)
    at Object.<anonymous> (/app/main.js:13:1)
    at Module._compile (node:internal/modules/cjs/loader:1358:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1416:10)
    at Module.load (node:internal/modules/cjs/loader:1208:32)
    at Module._load (node:internal/modules/cjs/loader:1024:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:174:12)
    at node:internal/main/run_main_module:28:49 {
  severity_local: 'ERROR',
  severity: 'ERROR',
  code: '22003',
  where: "unnamed portal parameter $1 = '...'",
  file: 'numutils.c',
  line: '873',
  routine: 'pg_strtoint64_safe',
  query: 'INSERT INTO scratchpad (n) VALUES ($1)',
  parameters: [
    '57896044618658097711785492504343953926634992332820282019728792003956564819968'
  ],
  args: [
    57896044618658097711785492504343953926634992332820282019728792003956564819968n
  ],
  types: [ 20 ]
}

Looking at the stack trace, the error seems to be coming from the postgreSQL server itself (since I see a TCP.onStreamRead in the stack). My guess is when preparing the statement, the wrong type is passed.

Run the reproduction in main.js against the NUMERIC(78, 0) table, then trace parameter handling from the query call through the reported postgres/cjs/src/query.js and connection.js stack entries. Compare the BigInt argument with the reported type [20]; done means the same value can be inserted without PostgreSQL treating it as an out-of-range bigint.