GET请求返回空数组而不是数组内容

Question

I'm a newbie, but trying to figure out why my GET request returns an empty array even though I know that the Mongo database collection isn't empty. Each word form in the WordForm collection has a "lexicalform" key whose value is a reference to a LexiconEntry object in that collection. When I submit a GET request with a LexiconEntry ObjectId as a parameter, it returns an empty array in stead of the array contents. Here are my files:

The GET route in my controller:

api.get('/wordforms/:id', (req, res) => {
    WordForm.find({lexiconentry: req.params.id}, (err, wordforms) => {
      if (err) {
        res.send(err);
      }
      res.json(wordforms);
    });
  });

The LexiconEntry model:

import mongoose from 'mongoose';
import WordForm from './wordform';
let Schema = mongoose.Schema;

let LexiconEntrySchema = new Schema({
  lexicalform: String,
  pos: String,
  gender: String,
  genderfull: String,
  decl: String,
  gloss: [String],
  meaning: String,
  pparts: [String],
  tags: [String],
  occurrences: Number,
  wordforms: [{type: Schema.Types.ObjectId, ref: 'Form'}]
});

module.exports = mongoose.model('LexiconEntry', LexiconEntrySchema);

The WordForms model:

import mongoose from 'mongoose';
import LexiconEntry from './lexiconentry';
let Schema = mongoose.Schema;

let WordFormSchema = new Schema({
  form: String,
  gender: String,
  case: String,
  number: String,
  lexicalform: {
    type: Schema.Types.ObjectId,
    ref: 'LexicalForm',
    required: true
  }
});

module.exports = mongoose.model('WordForm', WordFormSchema);

Answer 1

Based on your WordForm schema given above, there is no such property lexiconentry exists in WordForm schema as in your query below.

api.get('/wordforms/:id', (req, res) => {
    WordForm.find({lexiconentry: req.params.id}, (err, wordforms) => {
      if (err) {
        res.send(err);
      }
      res.json(wordforms);
    });
  });

The property called lexicalform in WordForm schema resembled the one you are trying above. So, you can change your code as below with this.

api.get('/wordforms/:id', (req, res) => {
    WordForm.find({lexicalform: req.params.id}, (err, wordforms) => {
      if (err) {
        res.send(err);
      }
      res.json(wordforms);
    });
  });