examples.md

examples

It attaches virtuals to result of find, findOne, findById, findByIdAndUpdate, and findOneAndUpdate if lean

const schema = new mongoose.Schema({
  name: String
});

schema.virtual('lowercase').get(function() {
  return this.name.toLowerCase();
});

schema.plugin(mongooseLeanVirtuals);

const Model = mongoose.model('Test', schema);

return Model.create({ name: 'Val' }).
  then(() => Promise.all([
    // You **must** pass `virtuals: true` to `lean()`
    Model.find().lean({ virtuals: true }),
    Model.findOne().lean({ virtuals: true }),
    Model.findOneAndUpdate({}, { name: 'VAL' }).lean({ virtuals: true })
  ])).
  then(results => {
    const [findRes, findOneRes, findOneAndUpdateRes] = results;
    assert.equal(findRes[0].lowercase, 'val');
    assert.equal(findOneRes.lowercase, 'val');
    assert.equal(findOneAndUpdateRes.lowercase, 'val');

    // Mongoose has an `id` virtual by default that gets the `_id` as a
    // string.
    assert.equal(findRes[0].id, findRes[0]._id.toString());
    assert.equal(findOneRes.id, findOneRes._id.toString());
    assert.equal(findOneAndUpdateRes.id, findOneAndUpdateRes._id.toString());
  });

It lets you choose which virtuals to apply

If you specify a list of virtuals in lean(), this plugin will only apply those virtuals. This lets you pick which virtuals show up.

const schema = new mongoose.Schema({
  name: String
}, { id: false });

schema.virtual('lowercase').get(function() {
  return this.name.toLowerCase();
});
schema.virtual('uppercase').get(function() {
  return this.name.toUpperCase();
});

schema.plugin(mongooseLeanVirtuals);

const Model = mongoose.model('Test2', schema);

return Model.create({ name: 'Val' }).
  then(() => Model.findOne().lean({ virtuals: ['uppercase'] })).
  then(result => {
    assert.equal(result.uppercase, 'VAL');
    assert.ok(!result.lowercase);
  });