Mongoose Cast Aggregation
A mongoose plugin that casts aggregation pipelines whenever possible.
Getting Started
Run:
npm install mongoose-cast-aggregation
Inject the plugin into mongoose:
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.
// After injecting the plugin
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:
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 } } }
]);