import { MongoClient, Decimal128, Db, Collection } from "mongodb" ; function createDecimal128FromHexBytes(hexBytes: string) { const buffer = Buffer.from(hexBytes, "hex" ); return new Decimal128(buffer); } const BAD_DECIMAL128_BYTES = "00000080bf48a113150dea9f9f74006c" ; function createBadDecimal128() { return createDecimal128FromHexBytes(BAD_DECIMAL128_BYTES); } function insertTestDocument(collection: Collection, d128: Decimal128) { return collection.insertOne({ name: "test" , value: d128, }); } async function displayDocument(collection: Collection, d128: Decimal128) { const result = await collection.aggregate([ { $match: { value: d128 } }, { $project: { _id: 0, value: 1, // for demo value: "$numberDecimal" : "127.50000000000000000000000000000000" toDouble: { $toDouble: "$value" }, // for demo value: 0 toString: { $toString: "$value" }, // for demo value: "0E-32" cmp0: { $cmp: [ "$value" , 0] }, // for demo value: 0 (equal) }} ]).toArray(); console.log( "\nAggregation result:" ); console.log(JSON.stringify(result, null , 2)); } async function testDocument(collection: Collection, d128: Decimal128) { await insertTestDocument(collection, d128); await displayDocument(collection, d128); } async function demo(collection: Collection) { await testDocument(collection, createBadDecimal128()); } async function main() { const client = new MongoClient( "mongodb: //localhost:27017/?directConnection= true " ); // Replica set mode await client.connect(); const db = client.db( "decimal128_bug_reproduction" ); const testCollection = db.collection( "test" ); try { await testCollection.deleteMany({}); await demo(testCollection); } finally { await client.close(); } } main(). catch (console.error);