Mark Spawning.directions as optional

[tiennou]

This property is only defined if it was passed as spawn options, or it got set through Spawn.spawning.setDirections. Otherwise it'll be undefined and the creep will default to [TOP].

Fixes #243.

Checklists

• Test passed
• Coding style (indentation, etc)
• Edits have been made to src/ files not index.d.ts
• Run npm run dtslint to update index.d.ts

[DiamondMofeng]

Thank you❤️. Anyway I think Typescript's Optional Propertiy Modifier ?: is more suitable in this case.

interface A {
  p?: number;
}

let a: A = {} // OK

interface B {
  p: number | undefined | null
}

let b: B = {} // Error: Property 'p' is missing in type '{}' but required in type 'B'.

Although we won't create a Spawning object, the former case expresses better.

You can accept suggested changes on the website. Then we are ready to go🚀

[tiennou]

There you go!

[DiamondMofeng]

LGTM