# How to find documents in Mongoose

By Atta Ur Rehman Shah (https://attacomsian.com/about). Published Jun 26, 2022. Topics: Node.js, Mongoose, MongoDB.
Canonical URL: https://attacomsian.com/blog/mongoose-find-documents

> A quick guide to learning about different ways to find one and more documents from a MongoDB collection.

Mongoose [models](https://attacomsian.com/blog/mongoose-models#querying-documents) provide several static methods to retrieve one and more documents from a MongoDB collection.

Let us say you have the following Mongoose model `Product` that contains information about the products you are selling on your website:

```javascript
const mongoose = require('mongoose')
const { Schema } = mongoose

const Product = mongoose.model(
  'Product',
  new Schema({
    name: String,
    color: String,
    price: Number
  })
)
```

## Find a single document

To retrieve a single document from a MongoDB collection, you can use the `findOne()` method:

```javascript
const doc = await Product.findOne({ name: 'MacBook Pro' })
```

The `findOne()` method takes in a JSON object as a [query filter](https://attacomsian.com/blog/mongoose-queries). If the filter object is `null` or `undefined`, Mongoose will send an empty command to retrieve an arbitrary document.

Mongoose provides another method called `findById()` to retrieve one document by its `_id`. This method takes in the document ID and returns a [promise](https://attacomsian.com/blog/promises-javascript) that resolves to a Mongoose document or `null` if no document was found.

```javascript
await Product.create({ _id: 'X2B' })

// { _id: 'X2B' }
const doc = await Product.findById('X2B')
```

The `findById()` method is just a wrapper on top of `findOne()`. When you call `findById()`, Mongoose calls `findOne()` under the hood to retrieve the requested document.

## Find multiple documents

To retrieve a list of all products in the collection, you can use the `find()` method with an empty object as the first parameter:

```javascript
const docs = await Product.find({})
```

The `find()` method is a powerful tool for querying a MongoDB database. It accepts a filter object and returns all documents that match the filter. The filter object can contain equality checks, comparisons, [regular expressions](https://attacomsian.com/blog/javascript-regular-expressions), and compositions.

The following example demonstrates how you can retrieves all black color products with a price range of 5 and 15:

```javascript
const docs = await Product.find({
  color: 'Black',
  price: {
    $gte: 5,
    $lte: 15
  }
})
```

What if you have millions of products in the collection? Loading all your products into memory at once is not a good idea.

To iterate over all products one at a time without loading them all into memory at once, you should use the `cursor()` [helper method](https://attacomsian.com/blog/mongoose-queries#streaming):

```javascript
const cursor = Product.find().cursor()

for (let doc = await cursor.next(); doc != null; doc = await cursor.next()) {
  console.log(doc)
}
```