Discussion on: Advanced TypeScript Types cheat sheet (with examples)

[Pedro Mutter]

Congratulations! Really good article, very useful! I would like to add the possibility to create your own type guards on the type guard section, here is an example:

[Skye Wu]

i think : obj is ImportantType is ok, but can be more simpler:

function isImportantType(obj: any): boolean {
  return obj.id && obj.requiredFiled;
}

[Pedro Mutter]

But it wouldn't be a type guard though.

[Skye Wu]

thanks for explain

[Todd Matheson]

That defeats the purpose of using the type guard altogether. Typescript won’t infer the type from that function. :obj is ImportantType is the what tells typescript what the passed parameters type is. Hence type guard.

[Skye Wu]

thanks for explain

[Ibrahima Ndaw]

Great! A really good example, I will add it to the article.