Mongoose Cast Aggregation

A mongoose plugin that casts aggregation pipelines whenever possible.


Getting Started

``
npm install mongoose-cast-aggregation
`

Inject the plugin into mongoose:

`js
import mongoose from 'mongoose';
import castAggregation from 'mongoose-cast-aggregation';

mongoose.plugin(castAggregation);
`

Or with CommonJS:

`js
const mongoose = require('mongoose');
const castAggregation = require('mongoose-cast-aggregation');

mongoose.plugin(castAggregation);
`

Now mongoose will cast the $match stage whenever possible. It casts the $match stage as long as no stage before it changed the resulting document shape from the original schema (e.g. $match, $limit, $sort, $skip, $sample, $search, and $searchMeta). It also casts query on $geoNear stages.

`js
const discountSchema = new Schema({
expiresAt: Date,
amount: Number
});

const Discount = mongoose.model('Discount', discountSchema);

const discounts = await Discount.aggregate([
// Will cast the amount to a number, and the timestamp to a date object
{ $match: { expiresAt: { $lt: Date.now() }, amount: '20' } }
]);
`

This works as well:

`js
const discounts = await Discount.aggregate([
{ $sort: { amount: -1 } },
{ $skip: 20 },
// Will cast the stage below to a date object, because the document shape hasn't changed yet.
{ $match: { expiresAt: { $lt: Date.now() } } },

// Will cast this one to numbers as well.
{ $match: { amount: { $gt: '80', $lt: '200' } } },
{ $project: { amountInUSD: '$amount' } },

// Will NOT cast this one, because we used a stage that changed the shape of the document.
// so using the string '100' here will not work, will have to use the correct type of number in order to get results.
{ $match: { amountInUSD: { $gt: 100 } } }
]);
``