TypeScript is surprisingly ok for compilers

Post by austin-cheney » Fri, Aug 18, 2023, 5:58 PM UTC

afavour wrote: post #175

austin-cheney wrote: post #172

Earlier quoted context omitted.

What you are advocating, the guessing about performance, is the premature optimization. Don't feel bad, most developers have no idea what that term really means. Here is the original essay where it comes from: http://web.archive.org/web/20130731202547/http://pplab.snu.a... Premature optimization is the extra effort required to alter work necessary to circumvent guessed optimization pitfalls. In the same breath Knuth…

> Don't feel bad, most developers have no idea Some advice I know you’ll ignore: your tone in the comments here is deeply patronising. You know absolutely nothing about me and yet are entirely comfortable dismissing my perspective as wrong simply because yours must be correct. It’s not an interesting or rewarding way to converse, it makes me want to stop talking to you as soon as I can. Which I’ll be doing here. Have…

Post by Zambyte » Fri, Aug 18, 2023, 6:04 PM UTC

thefaux wrote: post #168

grumblingdev wrote: post #116

TypeScript is an incredible language in general. The fact that Functions are Objects that can have properties/methods is supremely undervalued. Are there other languages that do this so nicely? It's the perfect blend of OO and functional. Programming is mostly about gradually figuring out the right design I find. JS/TS let's me evolve things naturally without big rewrites. function foo() {} function bar() {} function…

This blend of functional and oo programming was pioneered by scala.

Post by CharlieDigital » Fri, Aug 18, 2023, 6:10 PM UTC

nightpool wrote: post #184

CharlieDigital wrote: post #169

Earlier quoted context omitted.

The fact that Functions are Objects that can have properties/methods is supremely undervalued. Are there other languages that do this so nicely? It's the perfect blend of OO and functional. Yes. C#. The equivalent are `Func` and `Action` types representing functions with a return and without a return. In fact, the JavaScript lambda expression looks awfully familiar to C#. One of the snippets below is C# and the other…

this doesn't really address OP's point, where in JS you can do: const foo = () => doSomething; foo.help = "this is a description of the function"; const commands = [foo]; // print help commands.forEach(c => console.log(c.name, c.help || "No help is available for this function"); Presumably this isn't possible in C# because it's statically typed, so the object returned by "() => doSomething" can't be converted into on…

    var log = (object message) => Console.WriteLine(message);
    var foo = () => log("Hello, World");
    var fn1 = (foo, "This is the help text");

    var commands = new[] { fn1 };
    commands.ToList().ForEach(c => {
      var (fn, help) = c;
      log(fn.Method.Name);
      log(help ?? "No help is available for this function");
    });

    var log = (object message) => Console.WriteLine(message);
    var foo = () => log("Hello, World"); 
    
    var commands = new (Action fn, string? help)[] { 
      (foo, "This is the help text"), 
      (foo, null) 
    };
    
    commands.ToList().ForEach(c => {
      log(c.fn.Method.Name);
      log(c.help ?? "No help is available for this function");
    });

    var log = (object message) => Console.WriteLine(message);
    var foo1 = () => log("Hello, World");
    var foo2 = () => log("Hello, Neighbor");
    
    var bar = new[] {
      new {
        doSomething = foo1,
        help = "This is foo1's help text"
      },
      new {
        doSomething = foo2,
        help = "This is foo2's help text"
      },   
    };
    
    bar.ToList().ForEach(b => {
      var (fn, help) = (b.doSomething, b.help);
      fn();
      log(help);
    });

    > ...because it's statically typed

Post by gavinray » Fri, Aug 18, 2023, 6:17 PM UTC

domlebo70 wrote: post #24

To OP: You could avoid the visitor by using an IIFE style switch using the run utility fn: export const run = (f: () => T): T => f(); Now you can go: const inferred_type = run(() => { switch(blah) { ... } })

  const inferred = (() => "Hello")() // Inferred as "string"

  const myFn = () => { switch(...) }
  const inferred = myFn()

Post by cobbzilla » Fri, Aug 18, 2023, 6:53 PM UTC

jitl wrote: post #107

smcl wrote: post #53

Earlier quoted context omitted.

I haven't used it in a couple of years (tbh I may have to remove "full stack" and "Angular" from my CV...) but I don't recall TS compilation being particularly slow. Are people not happy with how quick it is, or do you have a particularly big/complex application you're working with?

Notion is more than 10k typescript files and we view typecheck slowness and memory pressure as an existential threat to our codebase. Right now our typecheck needs ~12GB of heap size but the memory needs have accelerated recently.