Refactor: Convert transpiler to an ES Module

transpiler.js

@@ -0,0 +1,17 @@
+/**
+ * Transpiles a string of Hi source code into JavaScript.
+ * @param {string} sourceCode The Hi source code.
+ * @returns {string} The equivalent JavaScript code.
+ */
+export function hi2js(sourceCode) {
+  // This will be replaced by a proper AST-based generator.
+  return sourceCode
+    // Comments: // ...
+    .replace(/^\s*\/\/.*/gm, (match) => match)
+    // Declaration: name: value -> let name = value;
+    .replace(/^(?!.*\/\/.*)([\w$]+)\s*:\s*(.*)/gm, 'let $1 = $2;')
+    // Assignment: name = value -> name = value;
+    .replace(/^(?!.*\/\/.*)([\w$]+)\s*=\s*([^:;].*)/gm, '$1 = $2;')
+    // Global output: _(...) -> console.log(...);
+    .replace(/^(?!.*\/\/.*)\s*_\((.*)\)/gm, 'console.log($1);');
+}