Use with feathers-mongo-aggregate easily

aggregate.ts

// more info https://github.com/sainf/feathers-mongodb-aggregate
//
// To use on all / before
//
// This adds the array to params.aggregate to find and get.
//
// Strips data starts with "_l_" (lowercase L) on update and patch, useful for clear keys like lookups
//
// Example
// aggregate([
//   {
//     $lookup: {
//       from: 'storage',
//       localField: '_id',
//       foreignField: 'productId',
//       as: '_l_stock',
//     },
//   },
//   {
//     ...
//   },
// ]),

import type { Hook, HookContext } from '@feathersjs/feathers'
import { MethodNotAllowed } from '@feathersjs/errors'

export default (options: any[]): Hook => {
  return async (context: HookContext) => {
    const { data, params, type, method } = context

    if (!(type === 'before'))
      throw new MethodNotAllowed('Only on type before')

    if (method === 'find' || method === 'get')
      params.aggregate = options

    if (method === 'update' || method === 'patch') {
      for (const [k] of Object.entries(data)) {
        if (k.startsWith('_l_'))
          delete data[k]
      }
    }

    return context
  }
}