Why does the 'mongoose' variable from the 'script.js' file contain the model from the 'schema.js' file on startup?

Question

Node.js

Faced with unusual behavior for me. There are 2 files in the same folder:
schema.js

var mongoose = require('mongoose');
var bugSchema = mongoose.Schema({
  name: String,
  value: Number
});
mongoose.model('Bug', bugSchema);

script.js

var mongoose = require('mongoose');
require('./schema');

Why does the 'mongoose' variable from the 'script.js' file contain the model from the 'schema.js' file on startup?

Answer 1

because require "executes the module" once,
when reconnecting it returns the previously loaded
mongose ​​module apparently has internal model registration.

Answer 2

Because mongoose.model('Bug', bugSchema);.
In the future, the scheme registered in this way can be used like this:

var mongoose = require('mongoose');
var Bug = mongoose.model('Bug');