CODEWITHSUNDEEP
javascript
TomFree
TomFree

Reputation: 1389

Typesafety in javascript or how to avoid pretty hard to detect type related errors

I come from the Java world, i.e. a typesafe world and am right now doing a couple of things for which I need client side execution using javascript.

I keep running into pretty hard to detect errors at times due to the non typification of JS and am wondering if there is any way to prevent it beforehand. E.g. setting sth like "use typification;" or via some tool that does these checks before executing like a compiler does.

E.g. last time was when I was creating a face in three.js. There depening on order of vertices a face is front-facing or not. I had mixed that up and then copy pasted parameters in which case I also copied a bracket too much so it ended up in the wrong place with just calling the method with one instead of three vertices which of course resulted in an error. However in line 2107 of three.js code and it took a while to figure out this little copy paste issue. Comparing to java the compiler would have directly complained that i try calling the method with 1 instead of 3 parameters...

Hope there is sth like it. Or do have some tips how to spot such things faster?

Cheers Tom

Upvotes: 2

Views: 163

Answers (2)

Jared Smith
Jared Smith

Reputation: 21926

You have a number of answers. But first, need to clarify: Java is not type-safe (see: NullPointerException, history of).

But to get closer to type-safety in any dynamic language you have the option to pepper your code with asserts. This can to some degree be automated, it may cause performance issues. This is the route I usually take, but I certainly wouldn't do it with three.js.

For JavaScript specifically, you have two additional options: TypeScript and Flow.

TypeScript is a dialect of JavaScript with type annotations that gets compiled down to plain JS. Flow is a static analyzer written in OCaml that tries to infer types in your JS code and check them.

Upvotes: 1

Spandan Thakur
Spandan Thakur

Reputation: 368

There are various linting tools which you can use to scan your javascript files before you actually use them. The popular ones in the industry are JSLint, JSHint, JSCS and ESLint.

They come inbuilt with various rule sets which you can configure and you can also add your own rules.

You can compare these to checkstyles and PMD from the JAVA world.

Upvotes: 1

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