please explain this function

[J. Kevin Robbins]

I'm really beginning to hate fat arrow functions. Can someone re-write this so the inner function is a regular, private function called from the outer function? No anonymous inner stuff, just split this into two functions so maybe I can begin to understand how it works.

Thank you.

getServer(id: number) {    const server = this.servers.find(      (s) => {        return s.id === id;      }    );    return server;  }

After this I've got one with nested functions. That will be fun. This stuff is giving me a headache.  

[Liutauras Vilda]

Kevin, nice to see you back.

I don't know the syntax of this language, but the logic what it does is pretty straight forward, right. What is the stuff you don't understand?

If that were Java, the more habitual code construct would look like:

public Server getServerById(String id) {
    for (Server server : this.servers) {
        if (server.getId().equals(id)) {
            return server;
        }
    }
}

The function you showed, is actually very similar what Java also has with streams, predicates... The find() method simply acts as a stream where you filter result by passing a predicate as a lambda function. i.e.:

List<String> names = Arrays.asList("Kevin", "Liutauras");

Optional<String> kevin = names.stream()
		.filter(name -> name.length() == 5)
		.findFirst();

[Liutauras Vilda]

Just googled a bit how TypeScript

Modern:

getServer(id: number) {
    const server = this.servers.find(
      (s) => {
        return s.id === id;
      }
    );
    return server;
}

Habitual (I might made some syntax mistakes) :

getServer(id: number) {
    let server = null
    for (let hulk in this.servers) {
        if (hulk.id === id) {
            server = hulk;
            break
		}
	}
    return server;
}

[J. Kevin Robbins]

Thanks, good to be back.

It helps to see that in a format that I'm familiar with. One thing I found confusing is the "(s)". I thought the item or items in parenthesis just before the => were parameters to the inner function. But in this case is doesn't look like a parameter but rather a variable that will receive the value of the first return. But that doesn't make sense because the "const server" is where the final result ends up. If it's a parameter, what's it's value? Confusing.

As for streams, I actually haven't done much Java, almost no version 8, in the last couple of years. Some Java 5 (yes, really) lots of SQL, some PHP (ugh), some AWS cloud stuff (that was fun) and then I got tossed into the deep end of the Angular pool where I seem to do more sinking that swimming. Routing has me pulling out what little hair I have left. I know lambdas will sink in eventually but it's still frustrating at this point. I find them very difficult to read.

I miss JSP's and jQuery. That I understood. But that's obsolete tech now. I've been job hunting since November and saw very, very few jobs looking for JSP. I start my new job on Monday as an Angular developer so I've been bingeing on it for over a month. All those tutorials are exhausting.

[Liutauras Vilda]

J. Kevin Robbins wrote:One thing I found confusing is the "(s)". I thought the item or items in parenthesis just before the => were parameters to the inner function. But in this case is doesn't look like a parameter but rather a variable that will receive the value of the first return. But that doesn't make sense because the "const server" is where the final result ends up. If it's a parameter, what's it's value?

Well, that (s) is a variable of iterable item. It could have been called "kevin" or "server" or something else, it is just a variable. Functional programming guys for some reason all the time choose to pick non-descriptive and cryptic names, not sure why, i.e.: 'e' stands for kind of 'element', but since 'e' became a non-written standard, in most tutorials probably you'd see 'e' regardless what it represents.

J. Kevin Robbins wrote:As for streams, I actually haven't done much Java, almost no version 8

Yeah, I really recommend to assign some time for that, because those concepts you'd see all over the place, whether it be Kotlin or Scala or JavaScript or other languages. In some languages they were since beginning, and for instance Lisp or Clojure or Haskell guys probably loops would scare off.

[J. Kevin Robbins]

I think the light bulb just came on. When you said iterate it clicked.

this.servers is a collection of JavaScript objects of server information. Sort of like an List of Objects in Java terms. "Find" iterates through that list (like a for loop) and (s) holds a single server record as Find iterates through the collection, hence it can be used for comparison in the equality test in the first return statement. I couldn't see where (s) was getting initialized with a value because I didn't equate find to a for loop.

It all makes sense now. I don't know why I didn't see it. Thank you!