Introducing SuperScript

Taeber Rapczak <taeber@rapczak.com>

Saturday 11 February 2023

Pitch

SuperScript is a subset of JavaScript with TypeScript's syntax for a subset of types.

There are:
  • No classes
  • No semi-colons
  • Everything is defined as const NAME = SOME_VALUE
    • Which means only big arrow functions () => {...}
    • I do mean const. No var. No let.
  • No async/await
  • No exceptions
    • OK to return new Error
    • No throws, try, catch, finally
  • The only form of imports allowed is: import defaultExport from "path/to/module"
  • Exports restricted to export default {...} at the end of a file
  • Type information is required
    • Except when returning void
    • Or if it's obvious
    • There's no need for const i: number = 10
Furthermore, I recommend:
  • Restrict names to [a-zA-Z0-9].
    • No underscores, no dollar signs, no emojis.
    • Except to signify an unused variable _unused
  • Using temporary variables over inlining (except in string templates)
  • Is it too late to add a pipe operator to TypeScript?

Example

import console from "./console"

const main = () => {
  console.log("hello, world")
}

export default {
  main
}
There are more examples:

Motivation

I've been writing JavaScript since you had to write <script language="javascript1.2"> with disclaimers like "This page works best in Netscape Navigator 4.0 at a resolution of 800x600" to safely use the freshest features.

There are definitely some features I'm happy were added since then, but it's always been a confusing language.

More recently, I've been programming in TypeScript. At one point, it seemed like everyone was creating a language that transpiled to JavaScript. I've forgotten most of them, but TypeScript remains and is thriving.

Unlike other attempts at replacing JavaScript, TypeScript did not try to create a brand new language, but enhanced the existing language. As a superset of JavaScript, all valid JavaScript code is also valid TypeScript code.

Microsoft took a page from C++'s book there. Cfront, the original compiler, translated C++ into C and supported all existing C syntax.

JavaScript: The Good Parts

I'm glad I mentioned C++.

See, just like C++, JavaScript has started evolving a bit too much. Maybe TypeScript is to blame or maybe NodeJS exposed more developers to the language once it jumped out of the browser. I don't know.

What I do know is that the requirement for adding new features to these languages isn't should the feature be added, but has any other language done anything remotely like it?

In 2008, Douglas Crockford wrote JavaScript: The Good Parts.

Most programming languages contain good and bad parts, but JavaScript has more than its share of the bad, having been developed and released in a hurry before it could be refined. This authoritative book scrapes away these bad features to reveal a subset of JavaScript that's more reliable, readable, and maintainable than the language as a whole—a subset you can use to create truly extensible and efficient code.

When I asked Crockford if pe would consider writing an updated version for 2023 the response was simply "it would be the exact same book."

That got me thinking... what would the "good parts" subset of JavaScript look like today?

Benefits

So far, this is a loose idea I had, but the benefits of using a subset of an existing language:
  • Tools already exist for the language
  • Editors already support it
  • Easily interoperable with existing libraries
Specifically, with TypeScript:
  • Compile using tsc
  • Lint using eslint with a few rules
  • Fewer ways to do the same thing in JavaScript, so it's easier to learn.
  • ChatGPT will automatically write your code for you!

The Future

I plan to write more if and when I develop this idea more, but what do you think?

Which features would you include in your JavaScript subset?

Do you want to help me develop this idea?