[00:00] In this exercise, we've slightly simplified our class CanvasNode declaration. We've said we don't need to worry about read-only-ness anymore, so we've just said x equals 0 and y equals 0. Look how beautiful that is. Very, very nice. And now in our tests, we have const CanvasNode equals new CanvasNode,

[00:17] and it should be working that CanvasNode.x starts as 0, CanvasNode.y starts as 0. But we now should be having a method on CanvasNode which says move. And move should move it to that location. So you pass in an x-coordinate and a y-coordinate,

[00:36] and then CanvasNode.x should then equal 10 and 20, which is the coordinates that we're passing in. Your job is to try to figure out a way to add that method to this class, passing in x and y, and making sure that it ends up with the right coordinates in place. Good luck.

In this exercise, we've simplified our `CanvasNode` class so that it no longer has read-only properties:

```typescript
class CanvasNode {
  x = 0;
  y = 0;
}
```

There is a new test case for being able to move the `CanvasNode` object to a new location:

```typescript
it("Should be able to move to a new location", () => {
  const canvasNode = new CanvasNode();

  expect(canvasNode.x).toEqual(0);
  expect(canvasNode.y).toEqual(0);

  canvasNode.move(10, 20); // red squiggly line under move

  expect(canvasNode.x).toEqual(10);
  expect(canvasNode.y).toEqual(20);
});
```

Currently, there is an error under the `move` method call because the `CanvasNode` class does not have a `move` method.

## Challenge

Your task is to add a `move` method to the `CanvasNode` class. This method should accept an `x` coordinate and a `y` coordinate as parameters, and move the `CanvasNode` object to the specified location seen in the test. There are two different ways to accomplish this task!

Methods are functions that are defined inside of a class.

[00:00] Okay, the way that we can do this is we can say move and we can declare this kind of like you would declare it on an object. Now this move is going to take an x which is going to be a number and a y which is going to be a number and then we're going to say this dot x equals x and this dot y equals y.

[00:18] Beautiful. So now we've just declared basically a method on this canvas node and we can call it and when you hover over a canvas node you'll get access to move x and y here as the members.

[00:29] Nice. So this is the first way. There is also a way that you can basically say move here is an actual arrow function instead of being kind of like a method.

[00:39] So if we look between the two here, if I just kind of copy one over and I'll just grab this, put it here, you can see that if we have move at the top here this is declaring an arrow function

[00:50] which basically means it gets auto bound to the class and this one is kind of like a method where this could technically sort of be kind of messed about with.

[00:59] So in general, I mean which one do I prefer? I'm not sure which one I prefer. I generally move to this but I really don't... I generally declare it as an arrow function just because I'm used to declaring arrow functions

[01:14] but in most cases you're not going to need to worry too much unless you're handling kind of like legacy React components or things like that. But these are the two main ways that you can declare methods. Both of them are pretty similar. Both of them get access to this and I think you shouldn't need to choose between them all that often.

There are two main ways to declare methods in classes in TypeScript.

## Technique 1

The first way to declare a method uses a syntax similar to how you would declare an object property.

In this case, we'll declare a `move()` method on the `CanvasNode` class, which will accept `x` and `y` as number arguments:

```typescript
class CanvasNode {
  x = 0;
  y = 0;

  move(x: number, y: number) {
    this.x = x;
    this.y = y;
  }
}
```

Once this method is declared, you can call it on a class instance, and upon hovering over the instance, TypeScript shows us the method signature:

```typescript
// inside the test case
canvasNode.move(10, 20);

// Hovering over `move` shows:
(method) CanvasNode.move(x: number, y: number): void
```

## Technique 2

The second way to declare a method uses an arrow function:

```typescript
class CanvasNode {
  x = 0;
  y = 0;

  move = (x: number, y: number) => {
    this.x = x;
    this.y = y;
  };
}
```

Using an arrow function automatically binds the method to the class, while the first technique doesn't.

## Choose Your Technique

As for which technique to use, it essentially boils down to personal preference. Both are similar to write, and both provide access to `this`.

The choice between the two shouldn't be a major concern most of the time, unless dealing with legacy React components or similar situations.

Learn two different ways to declare methods in JavaScript classes.

Declaring Methods in TypeScript Classes

Implement Class Methods in TypeScript

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Implement Class Methods in TypeScript

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