State and Decorate #

State and Decorate is a powerful concept for KingWorld but similar with a different purpose

You can customize and create a shortcut and adapt KingWorld to your liking.

To put it simply:

• State: set global mutable store accessible to Handler
• Decorate: set custom method accessible to Handler

The different is that state is a globally mutable store of any type while decorate is not. Decorate expected to be only a function assigned once.

app
    .state('version', 1)
    .decorate('getDate', () => Date.now())
    .get('/version', ({ 
        getDate, 
        store: { version } 
    }) => `${version} ${getDate()}`
)

Decorator function is directly assigned to Context while state is assigned to Context.store.

KingWorld handle type registration for both state, and decorate.

So you don't need to type it manually or afraid that you're using a wrong type.

TypeScript #

You can type state and decorator explictly using TypeScript with as:

app
    // Will type version as `number | null`
    .state('version', 1 as number | null)
    .get('/version', ({ 
        store: { version } 
    }) => version

If explictly typed doesn't type null or undefined, make sure to set strict to true in tsconfig.json:

// tsconfig.json
{
  "compilerOptions": {
    "strict": true
  }
}