- cross-posted to:
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- cross-posted to:
- [email protected]
- [email protected]
Meme transcription:
Panel 1: Bilbo Baggins ponders, “After all… why should I care about the difference between int and String?
Panel 2: Bilbo Baggins is revealed to be an API developer. He continues, “JSON is always String, anyways…”
To whoever does that, I hope that there is a special place in hell where they force you to do type safe API bindings for a JSON API, and every time you use the wrong type for a value, they cave your skull in.
Sincerely, a frustrated Rust dev
“Hey, it appears to be int most of the time except that one time it has letters.”
throws keyboard in trash
Rust has perfectly fine tools to deal with such issues, namely enums. Of course that cascades through every bit of related code and is a major pain.
Sadly it doesn’t fix the bad documentation problem. I often don’t care that a field is special and either give a string or number. This is fine.
What is not fine, and which should sentence you to eternal punishment, is to not clearly document it.
Don’t you love when you publish a crate, have tested it on thousands of returned objects, only for the first issue be “field is sometimes null/other type?”. You really start questioning everything about the API, and sometimes you’d rather parse it as
serde::Valueand call it a day.API is sitting there cackling like a mad scientist in a lightning storm.
True, and also true.
This man has interacted with SAP.
The worst thing is: you can’t even put an int in a json file. Only doubles. For most people that is fine, since a double can function as a 32 bit int. But not when you are using 64 bit identifiers or timestamps.
That’s an artifact of JavaScript, not JSON. The JSON spec states that numbers are a sequence of digits with up to one decimal point. Implementations are not obligated to decode numbers as floating point. Go will happily decode into a 64-bit int, or into an arbitrary precision number.
What that means is that you cannot rely on numbers in JSON. Just use strings.
Unless you’re dealing with some insanely flexible schema, you should be able to know what kind of number (int, double, and so on) a field should contain when deserializing a number field in JSON. Using a string does not provide any benefits here unless there’s some big in your deserialzation process.
What’s the point of your schema if the receiving end is JavaScript, for example? You can convert a string to BigNumber, but you’ll get wrong data if you’re sending a number.
What makes you think so?
const bigJSON = '{"gross_gdp": 12345678901234567890}'; JSON.parse(bigJSON, (key, value, context) => { if (key === "gross_gdp") { // Ignore the value because it has already lost precision return BigInt(context.source); } return value; }); > {gross_gdp: 12345678901234567890n}https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse
Because no one is using JSON.parse directly. Do you guys even code?
It’s neither JSON’s nor JavaScript’s fault that you don’t want to make a simple function call to properly deserialize the data.
I’m not following your point so I think I might be misunderstanding it. If the types of numbers you want to express are literally incapable of being expressed using JSON numbers then yes, you should absolutely use string (or maybe even an object of multiple fields).
The point is that everything is expressable as JSON numbers, it’s when those numbers are read by JS there’s an issue
Can you give a specific example? Might help me understand your point.
You HAVE to. I am a Rust dev too and I’m telling you, if you don’t convert numbers to strings in json, browsers are going to overflow them and you will have incomprehensible bugs. Json can only be trusted when serde is used on both ends
This is understandable in that use case. But it’s not everyday that you deal with values in the range of overflows. So I mostly assumed this is fine in that use case.
Relax, it’s just JSON. If you wanted to not be stringly-typed, you’d have not used JSON.
(though to be fair, I hate it when people do bullshit types, but they got a point in that you ought to not use JSON in the first place if it matters)
As if I had a choice. Most of the time I’m only on the receiving end, not the sending end. I can’t just magically use something else when that something else doesn’t exist.
Heck, even when I’m on the sending end, I’d use JSON. Just not bullshit ones. It’s not complicated to only have static types, or having discriminant fields
Well, apart from float numbers and booleans, all other types can only be represented by a string in JSON. Date with timezone? String. BigNumber/Decimal? String. Enum? String. Everything is a string in JSON, so why bother?
I got nothing against other types. Just numbers/misleading types.
Although, enum variants shall have a label field for identification if they aren’t automatically inferable.
Well, the issue is that JSON is based on JS types, but other languages can interpret the values in different ways. For example, Rust can interpret a number as a 64 bit int, but JS will always interpret a number as a double. So you cannot rely on numbers to represent data correctly between systems you don’t control or systems written in different languages.
No problem with strings in JSON, until some smart developer you get JSONs from decides to interchangeably use String and number, and maybe a boolean (but only
false) to show that the value is not set, and of coursenullfor a missing value that was supposed to be optional all along but go figure that it was