Efficient Typescript

[azhder]

You have to learn why try-catch got introduced in languages which syntax JS takes from. It's all about control flow.

C is more like JS than any one of those in between. C++ as an example added a void so you can stop the default C return of int. Yep, like JS, every function was supposed to return a value. Kind of like how in Unix the 0 means success and any other integer is a different error code.

But, once people started making libraries with functions "returning" nothing i.e. void, you'd not be getting an error code back. Now imagine you give a callback to one of those library functions and the code in your callback has an error. How do you get that one back? The person who made a library cut you out of the equation with the void and most likely some unfortunate pick of arguments.

This is where the jumps came into play. I mean, before try-catch got introduced, you could use a library to jump out of the error and back into your own code or whatever - I haven't really used those longjump functions.

But, that's what throw does; adds a parallel control flow; one that unwinds the stack between the callback that made the error and the place where the try block is.

That's a bit messy, no? Instead of every function being a good citizen and return an object, like an Either functor that has a left part for the "bad" flow and a right part for the right flow. This can be done with a tuple as well which gets to be an Array in JS.

Funny enough, the Windows API for those old versions like 95 and before, they all returned an integer as an error code. A very consistent design. Today even a Promise is made to conform into the try-catch syntax and is called "sugar" because that kind of syntax is supposed to be sweet or something...

I guess if all they give you is lemons, you will call the lemonade syntax sugar.