I'm new to react and as I'm looking at examples, I see that a lot of tutorials don't use `this.props` or `this.state` directly. Instead, they will set a const at the beginning of the function. I've used the two interchangeably without seeing any difference in functionality.

Are there any gains to using `const`?

ie. 

```
const {
    error
} = this.state;

{error && <p>{error.message}</p>}

```

vs

```
{this.state.error && <p>{this.state.error.message}</p>}

```