实例冲突-JSON对象

Question

I'm not doing something right.

Trying to create 2 instances of data models off my json model template file and use them but I'm obviously not getting 2 different instances of the model.

myModel.json

{
    "id": null
}

myNodeModule.js

var myModel = require('../../entities/myModel');

module.exports = {

    find: function *(id){
        var myModelInstance1 = myModel;
        myModelInstance1.id = 1;

        var myModelInstance12 = myModel;
        myModelInstance12.id = 2;

        found.push(myModelInstance11);
        found.push(myModelInstance12);

        console.log("id: " + found[0].id);
}

Problem : it logs "2" because for some reason it applies the last initialization for myModel1.

So how do you create 2 separate object instances of myModel.json?

Answer 1

Create a function instead, which returns the object and call it.

function myModelFact(){
  return {
      "id": null
  }
}

Answer 2

The problem is that requiring a JSON document creates an object instance, but returns a reference to that instance (objects are passed/assigned by reference). That means that when you assign myModel , which is a reference to the object to another variable, you are essentially assigning a pointer to that same object. Consequently, if you modify the reference, the single instance changes and that change reflects on all references to that instance.

Try something like this instead:

function _getModelInstance() {
    return require('../../entities/myModel');
}

module.exports = {

    find: function(id){
        var myModelInstance1 = _getModelInstance();
        myModelInstance1.id = 1;

        var myModelInstance12 = _getModelInstance();
        myModelInstance12.id = 2;

        found.push(myModelInstance11);
        found.push(myModelInstance12);

        console.log("id: " + found[0].id);
}

This code will create a new instance of the object from the JSON document on demand.