// require() some stuff from npm (like you were using browserify)
// and then hit Run Code to run it on the right
var mongoose = require('mongoose');

// Set up a Schema with some required elements, and a field with an array
var ThingSchema = ({
  name: {
    type: String,
    required: true
  },
  quantity: {
    type: Number,
    required: true
  },
  age: {
    type: Number,
    required: true
  },
  // NOTE! Quantity ane Name share the same name as fields in their parent
  things: [{
    quantity: {
      type: Number,
      required: true
    },
    name: {
      type: String,
      required: true
    },
    weight: {
      type: Number,
      required: true
    }
  }]
});

// Try to validate a document with none of the required fields
var doc1 = new mongoose.Document({
  things: [{}]
}, ThingSchema);

// The results don't display messages for things.name or things.quntity, but they DO for things.weight
doc1.validate(function (result) {
  document.getElementById('log1').value = JSON.stringify(result.errors, null, '  ');
});

// With values put in for name and quantity on the main doc, validation errors show up for things.name and things.quantity
var doc2 = new mongoose.Document({
  name: 'Thingamajig',
  quantity: 2,
  things: [{}]
}, ThingSchema);

doc2.validate(function (result) {
  document.getElementById('log2').value = JSON.stringify(result.errors, null, '  ');
});