Fix transpilation of typescript-specific class keywords

[askoufis]

Something in @babel/babel-plugin-transform-typescript@7.18.0 broke transpilation of typescript-specific class keywords. Users could run into this issue when updating to sku@11.6.0 because the version range of @babel/babel-plugin-transform-typescript was updated.

Something like:

export class MyClass {
  constructor(protected foo: number) {}
}

is being transpiled to:

var MyClass = /*#__PURE__*/_createClass(function MyClass(protected foo) {
//                               not valid javascript -> ^^^^^^^^^
  _classCallCheck(this, MyClass);
});

protected is a typescript-specific keyword, so this is invalid code.

I'm unsure as to why this has suddenly become an issue in that version of the babel plugin, but it turns out that babel presets are executed in reverse, and we had preset-typescript before preset-env in the presets array, meaning preset-tyepscript was executing after preset-env, but preset-env doesn't understand the protected keyword (because it's typescript), so 💥 .

This PR fixes the ordering of presets so preset-typescript executes before preset-env, and adds a test class in one of the test cases with a typescript file because there isn't really a good place to put it (suggestions welcome) and I didn't want to make the test run any longer than it already is.

[changeset-bot]

🦋 Changeset detected

Latest commit: 8522306

The changes in this PR will be included in the next version bump.

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[mrm007]

Nice work 🕵️