mongoose-8325e563-issue-repro

index.js

const mongoose = require('mongoose');


const MONGO_URI = 'mongodb://127.0.0.1:47018/mongoose-issue-test';

const childSchema = new mongoose.Schema();

childSchema.virtual('name')
  .set(function (values) {
    for (const [lang, val] of Object.entries(values)) {
      this.set(`name.${lang}`, val);
    }
  })
  .get(function () {
    return this.$__getValue(`name.${this.lang}`);
  });

childSchema.add({name: {en: {type: String}, de: {type: String}}});

const ChildModel = mongoose.model('Model', childSchema);

const ParentModel = mongoose.model('Parent', new mongoose.Schema({
  children: [childSchema],
}));


(async () => {
  mongoose.connect(MONGO_URI);
  const child = await ChildModel.create({name: {en: 'Stephen', de: 'Stefan'}});
  child.lang = 'en';
  console.log(child.name);
  const parent = await ParentModel.create({
    children: [{name: {en: 'Stephen', de: 'Stefan'}}],
  });
  parent.children[0].lang = 'de';
  console.log(parent.toJSON({getters: true}));
  mongoose.disconnect();
})();


/*
  output up to mongoose@6.3.4:

    Stephen
    {
      children: [
        {
          _id: new ObjectId("65f88a0fa4c14240fb3482c5"),
          name: 'Stefan',
          id: '65f88a0fa4c14240fb3482c5'
        }
      ],
      _id: new ObjectId("65f88a0fa4c14240fb3482c4"),
      __v: 0,
      id: '65f88a0fa4c14240fb3482c4'
    }

  output with mongoose >=3.6.5:

    Stephen
    […]/node_modules/mongoose/lib/document.js:3895
            branch[part] = clone(val, options);
                        ^

    TypeError: Cannot create property 'de' on string 'Stefan'
        at applyGetters ([…]/node_modules/mongoose/lib/document.js:3895:22)
        at Document.$toObject ([…]/node_modules/mongoose/lib/document.js:3544:5)
        at Document.toJSON ([…]/node_modules/mongoose/lib/document.js:4013:15)
        at clone ([…]/node_modules/mongoose/lib/helpers/clone.js:52:17)
        at cloneArray ([…]/node_modules/mongoose/lib/helpers/clone.js:164:14)
        at clone ([…]/node_modules/mongoose/lib/helpers/clone.js:35:12)
        at applyGetters ([…]/node_modules/mongoose/lib/document.js:3895:24)
        at Document.$toObject ([…]/node_modules/mongoose/lib/document.js:3544:5)
        at Document.toJSON ([…]/node_modules/mongoose/lib/document.js:4013:15)
        at […]/index.js:36:22
*/