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# Objects

Dicts are objects, access members with \['name'] or .name

```javascript
var person = {}; //{} 
var person1 = new Object();
```

## Iterate Over

```javascript
Object.keys(p).map(k => )
Object.entries(p).map(([k, v]) => )
Object.values(p).map(v => )

for (let key of Object.keys(players)) {
    //.......
}
```

## General

### Check in

```javascript
'x' in {'x': 1} //true
```

### Combine Objects

Objects/keys on the right override those to the left

```javascript
{...x, ...y, ...z, a: 1}
Object.assign(x, y, z) //
```

### Copy

```javascript
{...x}
Object.assign({}, x)
```

### Delete

```javascript
delete myObject.prop;
```

### Equality

\=== will do ptr equality

Use lodash .isEqual for deep equality

## Old Classes

```javascript
function Person(name) {
  this.name = name;
  this.greeting = function() {
    alert('Hi! I\'m ' + this.name + '.');
  };
}

var person1 = new Person('Bob'); //new returns obj
var person2 = new Person('John'); //contains a new definition of gretting
```

To define functions out of scope,

```javascript
function Test(a, b, c, d) {
  // property definitions
}

// First method definition
Test.prototype.x = function() { ... };

// Second method definition
Test.prototype.y = function() { ... };
```

Can always add new values

```javascript
person1.newv = "secretsss";
```

## Prototypes?

objects can have a **prototype object** that all instances inherit from, everyone inherits from object prototype

```javascript
Person.prototype
Object.prototype
```

Changes to prototype affect all people

```javascript
Person.prototype.farewell = function() {
  alert(this.name.first + ' has left. Bye for now!');
};
person1.farewell();
```

## Create

`Object.create` makes a new object with the object given as its prototype, basically defining a subclass

```javascript
var person3 = Object.create(person1);//copy constructor, (inherit from person1)
```

## Inheritance

Its a mess, stupid javascript didn't want to do this

```javascript
function Teacher(first, last, age, gender, interests, subject) {
    Teacher.prototype = Object.create(Person.prototype); //inherit from Person.prototype
    Teacher.prototype.constructor = Teacher; //you just replaced the constructor, add it back
    Person.call(this, first, last, age, gender, interests); //.call allows you to pass this setting it

  this.subject = subject;
}
```


---

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