If you create a basic class with a method in Typescript like this :

class MyClass {
  public myMethod() {
    return "Hello World";
  }
}

let instance = new MyClass()

function _init() {
  instance.myMethod();
}

and try to run pico-8-ts, you'll get a nasty error telling you :

attempt to index local 'myclass' (a function value)

If we look at compiled.js we can see what causes this :

var MyClass = /** @class */ (function () {
    function MyClass() {
    }
    MyClass.prototype.myMethod = function () {
        return "Hello World";
    };
    return MyClass;
}());
var instance = new MyClass();
function _init() {
    instance.myMethod();
}

The javascript transpiled by tsc targets ES5, so it doesn't use class and Pico 8 Lua doesn't support prototypes.

Except that if you change the tsconfig.json to target ES6, even if you get this correct javascript, the problem persists.

class MyClass {
    myMethod() {
        return "Hello World";
    }
}
let instance = new MyClass();
function _init() {
    instance.myMethod();
}

Pico 8 still cries about protoypes except we don't have any prototypes in our generated output anymore.

It's because of jspicl-cli.
In /node_modules/jspicl-cli/bin/cli at line 100 we can see that it uses Bublé to compile js into < ES2015.
By default, Bublé strips away classes and use protoypes instead, and that's what transforms our class.

I removed Bublé and got an error, so instead I've just added the option to skip over classes and leave them alone :

function getInputOptions({ input, output, ...jspiclOptions }) {
  return {
    input,
    plugins: [
      includePaths({
        paths: [path.resolve(input)]
      }),
+      buble({
+        transforms: {
+          classes: false,
+        }
+      }),
      {
        renderChunk: source => source.replace(/\/\/ <!-- DEBUG[^//]*\/\/\s-->/g, "")
      },
      jspiclPlugin(jspiclOptions)
    ]
  };
}

Now it works fine. Should we create another patch over jspicl-cli ? Or do we make a fork so we can change #1 , this and maybe even replace the jspicl dependency to @jspicl/jspicl so we can migrate to version 3.0.0 and enable ESM ?

I use node 18.1.0 and I tried this tool by creating a sample project by running these commands :

./bin/tspico8.js init -d test-project
./bin/tspico8.js run -d ./test-project/

After Typescript is done compiling and uglify is done compressing, when ./node_modules/.bin/jspicl-cli is ran, it just hangs there so I ran the jspicl-cli command manually and this is what I got :

node:internal/errors:466
    ErrorCaptureStackTrace(err);
    ^

TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension "" for /Users/Quentin/Documents/Projects/Native/Pico8/pico-8-typescript/node_modules/.pnpm/[email protected]/node_modules/jspicl-cli/bin/cli. Loading extensionless files is not supported inside of "type":"module" package.json contexts. The package.json file /Users/Quentin/Documents/Projects/Native/Pico8/pico-8-typescript/node_modules/.pnpm/[email protected]/node_modules/jspicl-cli/package.json caused this "type":"module" context. Try changing /Users/Quentin/Documents/Projects/Native/Pico8/pico-8-typescript/node_modules/.pnpm/[email protected]/node_modules/jspicl-cli/bin/cli to have a file extension. Note the "bin" field of package.json can point to a file with an extension, for example {"type":"module","bin":{"cli":"./bin/cli.js"}}
    at new NodeError (node:internal/errors:377:5)
    at Object.getFileProtocolModuleFormat [as file:] (node:internal/modules/esm/get_format:80:11)
    at defaultGetFormat (node:internal/modules/esm/get_format:122:38)
    at defaultLoad (node:internal/modules/esm/load:21:20)
    at ESMLoader.load (node:internal/modules/esm/loader:431:26)
    at ESMLoader.moduleProvider (node:internal/modules/esm/loader:350:22)
    at new ModuleJob (node:internal/modules/esm/module_job:66:26)
    at #createModuleJob (node:internal/modules/esm/loader:369:17)
    at ESMLoader.getModuleJob (node:internal/modules/esm/loader:328:34)
    at async Promise.all (index 0) {
  code: 'ERR_UNKNOWN_FILE_EXTENSION'
}

Node.js v18.1.0

I managed to get the tool working by renaming ./node_modules/jspicl-cli/bin/cli to cli.cjs and ./node_modules/jspicl-cli/bin/plugin to plugin.cjs.

I also needed to change the paths in cli.cjs and ./node_modules/.bin/jspicl-cli of course.

Resolve #1 and #2

This PR :

• Use @quentin_widlocher/jspicl-cli to :
  • Allow ESM usage with recent versions of NodeJS.
  • Fix the usage of prototypes for classes.
• Remove now-useless patch-package
• Target ES6 to fix classes in Javascript