DEV Community

Extending JSON for fun and profit

Klemen Slavič on October 28, 2018

header image by Steel's Fudge In the early days of JavaScript when asynchronous requests first enabled web authors to make requests to HTTP server...

Read full post

Guillaume Martigny • Oct 29 '18

Very neat article with inspiring code. I never thought of your "private class member" with symbols, this is amazing (Why use Symbol.for tho ? It would allow access with instance[Symbol.for("name")] ?!.

Another question, why use Map for the classes dictionary ? Object literal would make a more readable code (IMO of course).

const createClassLookup = (scope = {}) => (name) =>
  scope[name] || (global || window)[name];
const classes = {
  Drone,
};

Klemen Slavič • Oct 29 '18

Actually, yeah, you're right... I should've used Symbol('name') instead. My bad! I'll fix the examples.

In the case of the classes lookup, you might have to have some mapping between the value of the $type property and the actual classname if they happen to not coincide. But really, there's no reason to pick Map over an object if you're just mapping strings to objects. I just like to use Map instead of POJOs as hashmaps when they become highly polymorphic, as it doesn't create hidden classes on mutation.

Jaimie Malvi • Oct 28 '18

Awesome Article Klemen.

Would love to share JSON parser tool jsonformatter.org/json-parser

Ben Halpern • Oct 28 '18

Jaimie, you appear to be a sort of low-key spam account. But you've been on-platform for about a year and a half and you only have nine comments, all like this. So I'm not even mad, I'm impressed.

John Carroll • Oct 29 '18

Your comment made me click on Jaimie's profile. I don't see how you reached the spam conclusion. Clearly, a JSON parser tool is on-topic here, and past comments about the tool also seem to be on-topic.

Klemen Slavič • Oct 29 '18

I would be wary of these kinds of online tools; you may be exposing sensitive data to a 3rd party. It's easy to mistakenly leak configuration, passwords or keys accidentally this way.

Vaibhav • Oct 29 '18

TIL I qualify as a spam account.

Guillaume Martigny • Oct 29 '18

TIL Kate Upton really like JSON :D
pinterest.fr/pin/139470919694956648/

Klemen Slavič • Oct 29 '18

True, I could have framed it as, say, a saving mechanism for a game using *Storage. I just hope the idea carries over rather than the implementation details in the reader's mind. :)