nodejs/node

General chat about the Node.js JavaScript runtime

Salathiel Genèse

@SalathielGenese

No, sorry

Zerka1982

@Zerka1982

Thanks!

Jason Williams

@jasonwilliams14

hey folks. Was looking for some guidance on nodeJS. i just started to dig into nodejs, and want to build a small app that would basically capture request headers that come in, and then basically respond back with some response headers. I am looking for some pointers on where to look for that. I appreciate the help.

1 reply

Salathiel Genèse

@SalathielGenese

https://www.google.com/search?q=nodejs+tutorial&oq=nodejs+tutorial&sourceid=chrome&ie=UTF-8

Jordan Harband

@ljharb

surely you mean next, not nest?

Louis Law

@louiscklaw

May I know the "name" of these question marks?
Please leave me the name/keywords of this is good enough because it is hard to google for this symbol for me. i can do the rest study/read docs/test myself

thanks in advance...

Salathiel Genèse

@SalathielGenese

Optional chaining, @louiscklaw

2 replies

(on the right)

Just a normal string

(on the left)

Jordan Harband

@ljharb

@louiscklaw please don't cross-post; i answered you the same in the airbnb/javascript gitter (this was the best place to ask tho)

Kasir Barati

@kasir-barati

I am working with node-mongodb-drive and i can not use $merge stage in the aggregate. mongodb throw this error: MongoError: Unrecognized pipeline stage name: '$merge'.

what can i do?

the same aggregate works in the mongo-compass.

Zerka1982

@Zerka1982

@Zerka1982
Hi guys !
ANybody here to support me on one task
If user inputs an email for example@gmail.com , I would like to force the user not to add any extra letters after the .com
is there a way to do this please?

Salathiel Genèse

@SalathielGenese

@Zerka1982 , consider:

Input pattern attribute (HTML)
DOM form field custom validity + regular expression (JavaScript)
Or a combination of what precedes

NOTEWORTHY

I hope you have strong reasons to enforce such rules. Some emerging TLD and thus, email addresses may well have more that three letters at the end (as the spec suggests)... Which is a concern I have from time to time with online service rejecting .berlin, .name, even sometimes .cloud

Anyabuike Kingsley

@kingsleykbc

What is the best way to represent related data in an API response object?

E.g., Say I have an order object. What method would better represent it (relating to logic and performance)?

Prefixing the keys:

{
    "quantity": 2,
    "date": 237823872,
    "productID": 1
    "productName": "iPhone",
    "productSlug": "www.site.com/iphone",
    "sellerID": 2,
    "sellerName": "Apple",
    "sellerEmail": "apple.com"
    "price": 500.00,
    "paymentStatus": "Successful"
}

or nested:

{
    "quantity": 2,
    "date": 237823872,
    "product": {
        "id": 1
        "name": "iPhone",
        "slug": "www.site.com/iphone",
    },
    "seller": {
        "id": 2,
        "name": "Apple",
        "email": "apple.com"
    },
    "payment":{
        "price": 500.00,
        "status": "Successful"
    }
}

Marco Vinicio

@Mark-B-88

@kingsleykbc As far as logic, nested is much better because it's more detailed. So if you're working in a team, or you need someone to help you with your code, the nested approach makes more sense. As far as performance, that's something I've not entirely sure about.

Andres Mazzo

@andresmazzo

@kingsleykbc i agree with @Mark-B-88 . Performance could be a little more on nested objects due to serialization of json, which increase cpu load. But it only applies for high traffic and big objects to see a significant variation

Anyabuike Kingsley

@kingsleykbc

@Mark-B-88 , @andresmazzo Thanks a lot

Phuong Nguyen

@neunygph

this is the most active channel I have seen

Salathiel Genèse

@SalathielGenese

NodeJS 17.0.1 error (latest, Linux, x64)

$ node -v
bash: /home/salathiel/.local/bin/node/bin/node: cannot execute binary file: Exec format error

https://nodejs.org/dist/v17.0.1/node-v17.0.1-linux-x64.tar.xz

Jordan Harband

@ljharb

why are you installing node with something that's not nvm

Salathiel Genèse

@SalathielGenese

The habit, I guess - tar -xf archive -C target/

I just tested with v17.0.0 and no problem with that

Jordan Harband

@ljharb

tbf i don't have linux, but nvm install 17 worked fine on 17.0.1

Salathiel Genèse

@SalathielGenese

okay

zillerium

@zillerium

I want to setup class vars in nodejs, like you have in Java etc. I am seeing only the constructor, here is a code example -

class myclass {
    var carMake = 'Ford'

}

Jordan Harband

@ljharb

@zillerium a) do not strive to make anything like java, that's always a downgrade. b) class in JS is not really classes, it's good sugar for making a constructor function and a prototype object. a "class var" is probably meant as a static property on the constructor function.

you can't declare variables inside a class body, it's not a scope.

so you can do class X { static make = 'Ford'; } if you want

zillerium

@zillerium

@ljharb thanks

Jordan Harband

@ljharb

that's public tho

zillerium

@zillerium

what is public?

Jordan Harband

@ljharb

you can do class X { static #make = 'Ford'; } for private.

"public" is "reachable" - things on the outside can see and change it

"private" is "unreachable" - and unlike every other language, private in JS actually means private; there's no reflection mechanism whatsoever

zillerium

@zillerium

I was about to edit my code snippet with a method or func to update carMake, eg setCarMake(carMake){ this.carMake = carMake; // but not in a constructor}

Jordan Harband

@ljharb

and there's no "protected" because that concept doesn't make any sense in JS; things are either reachable or not

sure, you can do that in either case. but it makes more sense to have it be private if you want to provide a setter function

that way nobody can set it a different way

however, classes (like for most things) are not a great way to model cars, since they aren't an inheritance tree. they're more like a collection of traits and metadata.

zillerium

@zillerium

cars are just an example, I am not actually working with cars, but I did see a lot of car models in OO systems

Jordan Harband

@ljharb

sure, but most of those are bad examples that only really exist in university :-)

zillerium

@zillerium

to summarise, I can instantiate the class and set variables via the constructor but I cannot have just variables in the class which are modified by functions (eg setters and getters)?

Jordan Harband

@ljharb

you can have properties, but not variables

variables can only exist in a scope, and a class body isn't one

zillerium

@zillerium

About cars, there were commercial examples.

ekranoplan

@ekranoplan:matrix.org

[m]

to summarise, I can instantiate the class and set variables via the constructor but I cannot have just variables in the class which are modified by functions (eg setters and getters)?

I think this would accomplish what you're trying to do:

class Car {
  #fuel = 0;
  #make;

  constructor(make) {
    this.#make = make;
  }

  get make() { return this.#make; }

  addFuel(quantity) {
    this.#fuel += quantity;
  }
}

In this case, #fuel is a private "variable" that can be modified within functions (e.g. the addFuel method). Technically #make is also a variable but I have easily written it in such a way that you cannot modify the make after the car has been constructed (since a Corolla will always be a Toyota) - there is only a getter for the make and no setter, and the #make field is private so it's not exposed to clients.

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