Schema.prototype.pre()

Parameters

• The «String|RegExp» method name or regular expression to match method name

• [options] «Object»

• [options.document] «Boolean» If name is a hook for both document and query middleware, set to true to run on document middleware. For example, set options.document to true to apply this hook to Document#deleteOne() rather than Query#deleteOne().

• [options.query] «Boolean» If name is a hook for both document and query middleware, set to true to run on query middleware.

• callback «Function»

Defines a pre hook for the model.

Example

const toySchema = new Schema({ name: String, created: Date });
toySchema.pre('save', function(next) {
  if (!this.created) this.created = new Date;
  next();
});
toySchema.pre('validate', function(next) {
  if (this.name !== 'Woody') this.name = 'Woody';
  next();
});
// Equivalent to calling `pre()` on `find`, `findOne`, `findOneAndUpdate`.
toySchema.pre(/^find/, function(next) {
  console.log(this.getFilter());
});
// Equivalent to calling `pre()` on `updateOne`, `findOneAndUpdate`.
toySchema.pre(['updateOne', 'findOneAndUpdate'], function(next) {
  console.log(this.getFilter());
});
toySchema.pre('deleteOne', function() {
  // Runs when you call `Toy.deleteOne()`
});
toySchema.pre('deleteOne', { document: true }, function() {
  // Runs when you call `doc.deleteOne()`
});