I'd like to know if I understood the line from the code.

[terrea]

let allModels = {};

function createModel(Model, ...args) {
    let model = new Model(...args);

    model._id = Math.random().toString(36).slice(2);
    allModels[model._id] = model;

    return model;
}

let user = createModel(class User {
    constructor(name) {
        this.name = name;
    }
    sayHi() {
        alert(this.name);
    }
}, "Вася");

user.sayHi(); // Вася

alert( allModels[user._id].name ); // Вася

allModels[model._id] = model; I'm interested in this line, and I've learned that it's true. model._id from the site model copyed allModels?
Thank you for your help!

[jeanid]

That's right. model._id from the site model copyed allModels?

No, not right.

In this line

allModels[model._id] = model;

There are two actions:

1. Access to an equal value character model._id
2. The value in question is assigned model

So the object allModels keep all facilities that have been created by the function Model♪