Multiple decorators can be applied to a declaration, for example on a single line:

```typescript
@f @g x
```

On multiple lines:

```typescript
@f
@g
x
```

When multiple decorators apply to a single declaration, their evaluation is similar to function composition in mathematics. In this model, when composing functions f and g, the resulting composite (f ∘ g)(x) is equivalent to f(g(x)).

As such, the following steps are performed when evaluating multiple decorators on a single declaration in TypeScript:

The expressions for each decorator are evaluated top-to-bottom.
The results are then called as functions from bottom-to-top.
If we were to use decorator factories, we can observe this evaluation order with the following example:

```typescript
function first() {
  console.log("first(): factory evaluated");
  return function (target: any, propertyKey: string, descriptor: PropertyDescriptor) {
    console.log("first(): called");
  };
}

function second() {
  console.log("second(): factory evaluated");
  return function (target: any, propertyKey: string, descriptor: PropertyDescriptor) {
    console.log("second(): called");
  };
}

class ExampleClass {
  @first()
  @second()
  method() {}
}
```

Which would print this output to the console:

```typescript
first(): factory evaluated
second(): factory evaluated
second(): called
first(): called
```


9. Decorator Composition

Multiple decorators can be applied to a declaration, for example on a single line:

```typescript...

Brian

Brian

9. Decorator Composition