How to delete all documents of all collections in Mongoose

Question

Using the Mongoose ODM with a MongoDB instance, how can one delete all documents in all collections of the database instance, without necessarily destroying the collections themselves or their indexes?

For contrast:

await mongoose.connection.db.dropDatabase();

Deletes the given database, including all collections, documents, and indexes.

according to the Mongoose docs , which is not desired.

Answer 1

Iterate over all collections in the database given by the values of the Connection.prototype.collections hash, and use Query.prototype.deleteMany() to delete every document in the collection.

The deleteMany() query/operation is asynchronous (it returns a Query promise-like object). In order to iteratively perform the operations for all collections, we can map each collection to a promise with an asynchronous callback in which we await the call, and use Promise.all to resolve when all of the queries have resolved.

async function clearCollections() {
  const collections = mongoose.connection.collections;

  await Promise.all(Object.values(collections).map(async (collection) => {
      await collection.deleteMany({}); // an empty mongodb selector object ({}) must be passed as the filter argument
  }));
}