@sachin-chourasiya/mongoose-aggregation-builder

A simple, secure, and chainable MongoDB aggregation pipeline builder for Mongoose.
It makes complex aggregation queries easier to write, readable, and safe from injection risks.

🚀 Why Use This?

Writing raw MongoDB aggregation pipelines can be verbose and hard to maintain:

User.aggregate([
  { $match: { status: 'active' } },
  {
    $lookup: {
      from: 'orders',
      localField: '_id',
      foreignField: 'userId',
      as: 'orders',
    },
  },
  { $unwind: { path: '$orders', preserveNullAndEmptyArrays: true } },
  { $group: { _id: '$_id', totalOrders: { $sum: 1 } } },
  { $sort: { totalOrders: -1 } },
  { $limit: 10 },
]);

With @sachin-chourasiya/mongoose-aggregation-builder:

const pipeline = Agg()
  .filter({ status: 'active' })
  .join('orders', '_id', 'userId', 'orders')
  .unwind('orders', true)
  .countOrders()
  .sortBy('totalOrders', 'desc')
  .limit(10)
  .build();

User.aggregate(pipeline);

📦 Installation

npm install @sachin-chourasiya/mongoose-aggregation-builder

✨ Features

• Chainable API → Build pipelines step-by-step
• Secure → Sanitizes field names and prevents malicious stages
• Readable → No more deeply nested arrays of objects
• Reusable → Save and reuse pipelines easily
• TypeScript Friendly → Works with .d.ts type definitions (coming soon)

📚 Usage Examples

Example 1 — Basic Filtering & Projection

const Agg = require('@sachin-chourasiya/mongoose-aggregation-builder');

const pipeline = Agg()
  .filter({ isActive: true })
  .project({ name: 1, email: 1 })
  .build();

User.aggregate(pipeline);

Generated Pipeline:

[{ $match: { isActive: true } }, { $project: { name: 1, email: 1 } }];

Example 2 — Join with Another Collection

const pipeline = Agg()
  .filter({ status: 'active' })
  .join('orders', '_id', 'userId', 'orders')
  .unwind('orders')
  .build();

User.aggregate(pipeline);

Generated Pipeline:

[
  { $match: { status: 'active' } },
  {
    $lookup: {
      from: 'orders',
      localField: '_id',
      foreignField: 'userId',
      as: 'orders',
    },
  },
  { $unwind: '$orders' },
];

Example 3 — Counting & Sorting

const pipeline = Agg()
  .filter({ status: 'active' })
  .groupBy('_id', { totalOrders: { $sum: 1 } })
  .sortBy('totalOrders', 'desc')
  .limit(5)
  .build();

User.aggregate(pipeline);

🛡 Security

• Field Name Sanitization — prevents $ operator injection in keys
• Safe Stage Restriction — only allows MongoDB stages you enable
• No Eval or Function Execution — pure JSON pipelines
• Input Validation — ensures correct data types for filters, sorting, etc.

📖 API Reference

.filter(query)

Adds a $match stage to filter documents.

.project(fields)

Adds a $project stage.

.join(collection, localField, foreignField, as)

Adds a $lookup stage to join another collection.

.unwind(path, preserveNull = false)

Adds a $unwind stage.

.groupBy(id, accumulators)

Adds a $group stage.

.countOrders()

Custom helper → counts number of joined documents.

.sortBy(field, order = "asc")

Adds a $sort stage.

.limit(n)

Adds a $limit stage.

.build()

Returns the final aggregation pipeline array.

📄 License

MIT License © 2025