Classes, Properties, and Methods

Neo.mjs classes are standard JavaScript classes. Every source file you write will be a class definition, extending some Neo.mjs class.

import Base from '../../../node_modules/neo.mjs/src/core/Base.mjs';

class Mammal extends Base {
    static config = {
        className: 'Simple.example.Mammal'
    }
}

const myMammal = Neo.create(Mammal);

// Where Neo.mjs initializes the class and makes the class available elsewhere.
export default Neo.setupClass(Mammal);

In the example above, we're extending the Neo.mjs base class. The static config block is unique to Neo.mjs; it provides a way of defining special properties, such as the className seen above. Over time we'll go into more detail on the static config property.

The const myMammal = Neo.create(Mammal); statement creates an instance of our class. For the sake of our discussion we're putting that statement in the same source file where the class is defined, but normally your code would import the class elsewhere, and create instances as needed.

Let's add a name propery to the class.

import Base from '../../../node_modules/neo.mjs/src/core/Base.mjs';

class Mammal extends Base {
    static config = {
        className: 'Simple.example.Mammal',
        name     : 'Anonymous'
    }
}

const myMammal = Neo.create(Mammal);
console.log(myMammal.name); // Logs "Anonymous"
myMammal.name = 'Herbert';
console.log(myMammal.name); // Logs "Herbert"

export default Neo.setupClass(Mammal);

In Neo.mjs, instance properties are usually added in the static config block.
The static config block does two things:

• It formally describes the properties API for your class.
• It lets Neo.mjs manage the initialization and lifecycle of those properties.

Think of the static config block as "these are the properties that can be set as instances are created." Config properties can be introduced anywhere in the class hierarchy.

Since our class defines a name property, we can specify that when creating the instance, using the second argument to the create method.

const myMammal = Neo.create(Mammal, {
    name: 'Creature'
});
console.log(myMammal.name); // Logs "Creature"

Since you define those properties, you can look for them in class methods and use them as needed. Let's add a speak() method that uses the name property.

import Base from '../../../node_modules/neo.mjs/src/core/Base.mjs';

class Mammal extends Base {
    static config = {
        className: 'Simple.example.Mammal',

        name: 'Anonymous'
    }
    speak(){
        console.log(`${this.name} is grunting`);
    }
}

const myMammal = Neo.create(Mammal, {
    name: 'Creature'
});

myMammal.speak(); // Logs "Creature is grunting."

export default Neo.setupClass(Mammal);