Mongoose: Search documents by keywords (text search)

Searching documents by keywords is a common requirement for modern applications. Mongoose, as a powerful Node.js ORM for MongoDB, offers capabilities to perform efficient text searches on document fields.

Enabling Text Search in Mongoose

To begin performing text searches with Mongoose, we need to create a text index on the fields we want to search. The following example shows how to define a text index in a Mongoose schema:

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const blogPostSchema = new Schema({
  title: { type: String, required: true },
  content: String
});

blogPostSchema.index({ title: 'text', content: 'text' });

const BlogPost = mongoose.model('BlogPost', blogPostSchema);

Basic Text Search

After setting up the schema, you can perform a basic text search using the $text operator:

BlogPost.find({ $text: { $search: 'keyword' } })
   .then(posts => {
     console.log(posts);
   })
   .catch(err => {
     console.error(err);
   });
 

Using Text Score

With text search, Mongoose can also return a relevance score:

BlogPost.find({ $text: { $search: 'keyword' } },
   { score: { $meta: 'textScore' } })
   .sort({ score: { $meta: 'textScore' } })
   .then(posts => {
     console.log(posts);
   })
   .catch(err => {
     console.error(err);
   });
 

Advanced Text Search Techniques

For more complex search requirements, Mongoose text search supports phrases, negations, and more.

Searching for Phrases

To search for an exact phrase, use double quotes around the phrase:

BlogPost.find({ $text: { $search: '"Specific phrase"' } })
   .then(posts => {
     console.log(posts);
   })
   .catch(err => {
     console.error(err);
   });

Excluding Words

You can exclude documents that contain a specific word by prefixing a minus sign (-) to the word:

BlogPost.find({ $text: { $search: 'keyword -unwanted' } })
   .then(posts => {
     console.log(posts);
   })
   .catch(err => {
     console.error(err);
   });
 

Combining Text Search with Other Queries

Text search can be combined with other Mongoose query operators to refine results.

Combining with Other Criteria

Let’s find documents based on text search and a date range:

BlogPost.find({
   $text: { $search: 'keyword' },
   createdAt: {
     $gte: new Date('2024-01-01'),
     $lt: new Date('2024-12-31')
   }
 })
 .then(posts => {
   console.log(posts);
 })
 .catch(err => {
   console.error(err);
 });
 

Using RegExp for Partial Matches

While not a full text search, for partial matching, regular expressions can be used:

BlogPost.find({ title: { $regex: '.*key.*', $options: 'i' } })
 .then(posts => {
   console.log(posts);
 })
 .catch(err => {
   console.error(err);
 });
 

Final Words

While Mongoose text search is powerful, it’s essential to consider its impact on performance, especially with large datasets. Indexing, query optimization, and database design play significant roles in the search performance.

Text search in Mongoose is a robust feature that can significantly enhance the user experience by allowing users to search through documents using keywords. Setting up text indexes and using the right query techniques are necessary for building efficient search capabilities into your applications.