> For the complete documentation index, see [llms.txt](https://nicollaslopes.gitbook.io/estudos/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://nicollaslopes.gitbook.io/estudos/javascript/classes.md).

# Classes

* this

Objetos não contem um escopo próprio.

Fazendo dessa forma, o this referencia o window, que é escopo global.

 Arrow functions não se conectam com o this da mesma forma que function declaration.

```javascript
const person = {
    name: "Nicollas",
    getName: () => {
        return this.name
    }
}

console.log(person.getName()) // undefined
```

Fazendo assim, funciona corretamente

```javascript
const person = {
    name: "Nicollas",
    getName: function() {
        return this.name
    }
}

console.log(person.getName())  // Nicollas
```

Evitando o this

```javascript
const person = {
    name: "Nicollas",
    getName: () => person.name
}

 console.log(person.getName()) 
```

* Prototype

Em JavaScript, quando um objeto é criado, ele possui automaticamente uma propriedade que referencia um outro objeto. Esse outro objeto é chamado de prototype. Todo objeto em JavaScript herda propriedades e métodos do seu prototype ascendente. Ou seja, o objeto acessa propriedades e métodos do seu protótipo ascendente. Essas propriedades não pertencem ao objeto em si, mas sim ao prototype do objeto. 

* Desestruturação de objetos

```javascript
const person = {
    name: 'Nicollas',
    age: 26
}

const { age } = person

console.log(age)  // 26
```

Se quiser renomear, pode-se utilizar:

```javascript
const { age: idade } = person

console.log(idade)  // 26
```

* JSON

```
{
    "nome": Nicollas,
    "idade": 26,
    "hobbies": ["Academia", "Ler"],
    "estudaJavascript": true
}
```

* POO

```javascript
class Person {
    constructor(firstName, lastName, age) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.age = age;
    }
}

const person = new Person('Joao', 'Da silva', 23);
console.log(person); // Person { firstName: 'Joao', lastName: 'Da silva', age: 23 }
```

* super, constructor, extends

```javascript
class Animal {
    constructor(name) {
        this.name = name
    }

    speak() {
        console.log(`${this.name} made some noise`);
    }
}

class Cat extends Animal {
    constructor(name) {
        super(name);
    }
}

const cat = new Cat('Ari');
cat.speak();
```

* static

```javascript
class Person {
    
    static speak() {
        console.log('Hello World!');
    }
}

Person.speak(); // Hello World!
```

* get/set


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