/*The pre hook is supposed to populate the teacher field, but for some reason it didn't.Somehow when populate directly from the controller it works!*/ exports.getAssignment = catchAsync(async (req, res) => { const assignment = await Assignment.findById(req.params.id).populate( 'teacher' ); if (!assignment) { return next(new AppError('No assignment found with this ID', 404)); } res.status(200).json({ status: 'success', assignment, }); }); /*But when I use with the pre hook it doesn't get excuted! */ const mongoose = require('mongoose'); const assignmentSchema = new mongoose.Schema( { teacher: { type: mongoose.Schema.ObjectId, ref: 'User' }, group: { type: mongoose.Schema.ObjectId, ref: 'Group' }, AssignedAt: { type: Date, default: Date.now() }, }, { toJSON: { virtuals: true }, toObject: { virtuals: true } } ); const Assignment = mongoose.model('Assignment', assignmentSchema); assignmentSchema.pre('findById', function (next) { console.log('is this running'); this.populate({ path: 'teacher', select: 'firstName', }); next(); }); module.exports = Assignment;En la documentación defindById() se indica que:
Esta función activa el siguiente middleware.
findOne()
findById() tampoco se mencionaen la lista de middleware de consulta .
Así que prueba esto:
assignmentSchema.pre('findOne', function (next) { … })Además, aquí se indica que el middleware debe declararse antes de crear el modelo:
assignmentSchema.pre('findOne', function (next) { … }) const Assignment = mongoose.model('Assignment', assignmentSchema);