Throw if name is empty

[volkanunsal]

Leaving the name empty is a frequent source of bugs and errors, since I use lambda functions, and forget to add the name field. e.g.

pure.join(scope, cloud.stack(() => ({}))) 

Would it be possible to create an invariant to check the name field? And even better would be if I can skip the empty lambda altogether:

pure.join(scope, cloud.stack('MyStack')) 

It would remove a lot of boilerplate.

[fogfish]

Thank you for raising this!

Unfortunately, this is a limitation of JavaScript, anonymous/lambda function do not have name attribute https://github.com/fogfish/aws-cdk-pure/blob/master/pure/src/index.ts#L60

const MyFun = (): ddb.DynamoProps => ...
pure.iaac(ddb.Dynamo)(MyFun) // the name attribute is define to `MyFun`

pure.iaac(ddb.Dynamo)((): ddb.DynamoProps => ...) // the name attribute is not defined

This is not nice, I'd like to use anonymous (lambda) functions too. It simplify the design. The function iaac allows you to define a name but I would not recommend it (const MyFun + pure.iaac is really the same)

pure.iaac(ddb.Dynamo)((): ddb.DynamoProps => ..., 'MyFun') 

Unfortunately, I do not have a perfect solution to use pure anonymous (lambda) functions. I can introduce any number of functions to lift lambda to IPure type but as I said earlier syntactically it would be same as const MyFun, e.g.

const MyFun = (): ddb.DynamoProps => ...
pure.iaac(ddb.Dynamo)(MyFun)

// vs

pure.iaac(ddb.Dynamo)(pure.lift('MyFun', (): ddb.DynamoProps => ...))

I hope I've understood your issue properly. If not could you please share code snippet with a problem.

[fogfish]

Speaking only about this code:

export function iaac<Prop, Type>(f: Node<Prop, Type>): (pure: IaaC<Prop>, name?: string) => IPure<Type> {
  return (pure, name) => unit(
    (scope) => new f(scope, name || pure.name, pure(scope))
  )
}

Indeed, it make sense either to disable a type of anonymous function or raise exception if name is not defined to prevent bugs. I'll definably improve this block with better error handling.

[volkanunsal]

I've tried to make the function input polymorphic in my code. This is my solution (WIP)

export declare function iaac<Prop, Type>(
  f: Node<Prop, Type>
): (pure: IaaC<Prop>, name?: string) => IPure<Type>;
export declare function iaac<Prop, Type>(
  f: Node<Prop, Type>
): (name: string) => IPure<Type>;
export function iaac<Prop, Type>(
  f: Node<Prop, Type>
): (...args: unknown[]) => IPure<Type> {
  return (...args) => {
    let id!: string;
    let pure: IaaC<Prop> = () => ({} as Prop);

    if (typeof args[0] === 'string') {
      if (!args[0]) {
        id = args[0];
      }
    } else if (typeof args[0] === 'function') {
      pure = args[0] as IaaC<Prop>;
    }

    if (typeof args[1] === 'string' && !args[1]) {
      id = args[1];
    }

    if (pure.name) {
      id = pure.name;
    }

    if (!id) throw new Error('Id is required.');

    return unit((scope) => new f(scope, id, pure(scope)));
  };
}

The problem I'm running into is this error:

Overload signatures must all be ambient or non-ambient.ts(2384)

This looks a bit ugly, but it would allow for a very simple end user API:

pure.join(scope, cloud.iaac(Stack)('MyStack'))

[fogfish]

Are you trying to make a construct that takes empty (aka default properties)?

One idea, just make type (pure: IaaC<Prop>) => IPure<Type> composable.

const MyStack = cloud.iaac(Stack)
pure.join(scope, MyStack)

[volkanunsal]

Are you trying to make a construct that takes empty (aka default properties)?

Yes, exactly.

[fogfish]

Could you please clarify your usage of "empty properties"? In my life with AWS CDK, I've never used 'em? I've always needs to defined for props to resources.

[volkanunsal]

The most common usecase for me is the Topic class. All the properties are optional. If you don't provide a displayName, one is generated for you.

These are the constructs where I used empty properties:

topic
que
logGroup
fargateTaskDef
logGroup
stack