Fix typescript issues, refactor a bit (#4)

* Fix TypeScript issues

Commander can automatically import files for us by specifying
'executableFile' for commands. This unfortunately doesn't work well with
TypeScript, which was why we were using `node -r ts-node` to run the CLI
instead of `ts-node`. This setup to get commander working was also
causing other issues with file imports.

This commit updates so we now manually import files for commands, which
enables us to revert the less-conventional TypeScript config.

* Refactor file structure, update how commands run

Since the tool is only React Native for now, it didn't seem necessary to
have the 'react-native' directory. Moved to 'src'.

Also created utility for importing commands for commander

* Run ts-node with esm loader

This fixes the issue where we are unable to run packages
that only export ES Modules. It's possible we will still run into some
issues with this configuration since ESM support is still experimental
on the TypeScript side.

Relevant issue: TypeStrong/ts-node#1007
ESM loader docs: https://typestrong.org/ts-node/docs/imports/#native-ecmascript-modules

bin/belt

@@ -1,3 +1,3 @@
 #!/usr/bin/env bash
 
-node -r ts-node/register ./react-native/react-native.ts "$@"
+yarn ts-node ./src/cli.ts "$@"

package.json

@@ -3,6 +3,7 @@
   "version": "1.0.0",
   "description": "Monorepo for project bootstrapping CLIs",
   "main": "index.js",
+  "type": "module",
   "scripts": {
     "belt": "bin/belt",
     "test": "echo \"Error: no test specified\" && exit 1"

src/cli.ts

@@ -0,0 +1,25 @@
+import { program } from "commander";
+import buildAction from "./util/buildAction";
+
+console.log("React Native 🎉");
+
+export default function runCli() {
+  program
+    .name("thoughtbelt")
+    .description(
+      "Perform React Native and Expo setup and redundant tasks without your pants falling down!"
+    )
+
+    .command("eslint")
+    .description("Configure ESLint")
+    .action(buildAction(import("./commands/eslint")));
+
+  program
+    .command("prettier")
+    .description("Configure Prettier")
+    .action(buildAction(import("./commands/prettier")));
+
+  program.showHelpAfterError().parse();
+}
+
+runCli();

src/commands/eslint.ts

@@ -0,0 +1,3 @@
+export default function runEslint() {
+  console.log("ESLint!");
+}

src/commands/prettier.ts

@@ -0,0 +1,3 @@
+export default function runPrettier() {
+  console.log("Prettier!");
+}

src/util/buildAction.ts

@@ -0,0 +1,17 @@
+type AsyncModule = Promise<{
+  default: (...args: unknown[]) => void;
+}>;
+
+/**
+ * builds the action function that is passed to Commander's
+ * program.action.
+ * Eg: program.action(
+ *   buildAction(import('./commands/prettier))
+ * )
+ */
+export default function buildAction(asyncModule: AsyncModule) {
+  return async (...args: unknown[]) => {
+    const module = await asyncModule;
+    module.default(args);
+  };
+}

tsconfig.json

@@ -1,17 +1,18 @@
 {
   "compilerOptions": {
     "allowSyntheticDefaultImports": true,
-    "lib": ["es2019"],
     "target": "es2019",
-    "module": "commonjs",
-    "strict": true,
+    "module": "ES2020",
     "moduleResolution": "node",
-    "noImplicitThis": true,
-    "noUnusedLocals": true,
+    "strict": true,
     "sourceMap": true,
     "outDir": "./build",
     "skipLibCheck": true,
     "types": ["node"]
   },
-  "include": ["./**/*"],
+  "ts-node": {
+    "esm": true,
+    "experimentalSpecifierResolution": "node"
+  },
+  "include": ["./**/*"]
 }