I managed to get this to work using info from this article. Good thing is, this made the kata work in 4.9. Bad thing is, it probably makes the description outdated. I do not understand TS well enough to update the description, the most I can do is to blindly make the information from the description atch the information from the article, without understanding it well. But if someone would want to give it a shot, go ahead.

Singleton is mostly considered an anti-pattern in JS/TS tho

expected { a: 1 } to deeply equal { a: 1 }

The constructor function for Animal should accept 4 arguments in total in the following order: name, age, legs, species, status.

The description is incorrect: there are 5 arguments, not 4.

Hi,

I think this kata is not compatible with TS 4.9+ (4.9 just has been made available on CW). I think it's because of the new Auto-Accessors feature: using this just before applying the mixins:

class Person implements Serializable {
  constructor (public firstName?: string, public lastName?: string) {}
  // @ts-ignore strictPropertyInitialization
  serialize: () => string;                      // <<< troubles
  // @ts-ignore strictPropertyInitialization
  deserialize: (source: string) => void;        // <<< troubles
}

console.log(Object.getOwnPropertyNames(new Person()))
  // 4.2: [ 'firstName', 'lastName' ]
  // 4.9: [ 'firstName', 'lastName', 'serialize', 'deserialize' ]

meaning applyMixins is still updating the prototype of Person/Robot, but those are shadowed anyway by the instance accessors, which are returning undefined (because of the way the Person class is defined).

I'm not sure what should be done (retire the kata? maybe there is a way to fix that anyway?)

Anyone?

As we are in TypeScript, the TypeScript string type should be used.
Spaces are also the key for a readable piece of code.

https://stackoverflow.com/questions/14727044/what-is-the-difference-between-types-string-and-string

var str: String = new String("Hello world"); // Uses the JavaScript String object

var str: string = String("Hello World"); // Uses the TypeScript string type

Clever solution.

This kata is more testing basic JavaScript logic than it is types knowledge.

Disappointed.

1. The latest version of the Basic Types page (from TypeScriptLang.org) does not reference hex values
2. The TSC will not accept a value of 0xf00d for the hex value. It appears it once did (since this is what accepted answers show)? But it does not anymore. I got an error. This (or the instructions) need fixed.
3. The instructions say f00d when they should say 0xf00d for the hex value. Instructions are bad.

This kata needs some help. Very disappointed.

same here.
I do find descriptions of SQL tasks bit cryptic.

What is the difference between type String vs. string?

Not an issue, more like a suggestion, but reading tutorials is also every beginners' day-to-day operation ^^