Mongoose is a MongoDB object modeling tool designed to work in an asynchronous environment.

Everything in Mongoose starts with a Schema. Each schema maps to a MongoDB collection and defines the shape of the documents within that collection.

Mongoose makes it painlessly easy to work with MongoDB database.

We can easily structure our database using Schemas and Models, Automate certain things when record is added or updated using Middlewares/Hooks and easily get the data we need by querying our models.

Important Links

• Mongoose Quickstart
• Mongoose GitHub Repository
• Mongoose Documentation
• Mongoose Plugins

In mongoose, Middlewares are also called as pre and post hooks.

There are two types of middleware

Both of these middleware support pre and post hooks.

1. Document middleware

   Its supported for document functions init, validate, save and remove

2. Query middleware

   Its supported for query functions count, find, findOne, findOneAndRemove, findOneAndUpdate, insertMany and update.

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Pre and Post hooks

There are two types of Pre hooks

1. serial

   As the name suggests, Its executed in serial order i..e one after another

2. parallel

   Parallel middleware offers more fine-grained flow control and the hooked method is not executed until done is called by all parallel middleware.

Post Middleware are executed after the hooked method and all of its pre middleware have been completed.

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hooked methods are the functions supported by document middleware. init, validate, save, remove