LosaDev Tools: Lost Saga modding tools in the browser

app/tools/port-module.mjs

@@ -0,0 +1,74 @@
+// Mechanical CommonJS -> ESM conversion of desktop LS Tools modules (no logic changes).
+// usage: node tools/port-module.mjs <reference file> <output file>
+//   const x = require("y");            -> import x from "y";
+//   const { a, b: c } = require("y");  -> import { a, b as c } from "y";
+//   module.exports = { A, B: C };       -> export { A, C as B };
+//   module.exports = X;                 -> export default X;
+// Relative requires get ".js" added. Anything else that is not this simple is reported, so it
+// gets ported by hand instead of guessed.
+import fs from "node:fs";
+import * as acorn from "acorn";
+
+const [src, dst] = process.argv.slice(2);
+let text = fs.readFileSync(src, "utf8");
+const problems = [];
+
+const fixSpec = (s) => (s.startsWith(".") && !s.endsWith(".js") && !s.endsWith(".json") ? s + ".js" : s);
+
+text = text.replace(/^const (\w+) = require\("([^"]+)"\);?$/gm, (_, name, spec) => `import ${name} from "${fixSpec(spec)}";`);
+text = text.replace(/^const \{([^}]+)\} = require\("([^"]+)"\);?$/gm, (_, names, spec) => {
+	const list = names.split(",").map((n) => n.trim()).filter(Boolean).map((n) => n.replace(/^(\w+)\s*:\s*(\w+)$/, "$1 as $2"));
+	return `import { ${list.join(", ")} } from "${fixSpec(spec)}";`;
+});
+// module.exports = { ... } is parsed (acorn), not split on commas: values can be whole arrow
+// functions or methods with commas inside.
+{
+	const ast = acorn.parse(text, { ecmaVersion: "latest", sourceType: "module", allowReturnOutsideFunction: true, allowAwaitOutsideFunction: true });
+	const st = ast.body.find(
+		(n) =>
+			n.type === "ExpressionStatement" &&
+			n.expression.type === "AssignmentExpression" &&
+			n.expression.left.type === "MemberExpression" &&
+			n.expression.left.object.name === "module" &&
+			n.expression.left.property.name === "exports" &&
+			n.expression.right.type === "ObjectExpression",
+	);
+	if (st) {
+		const consts = [];
+		const list = [];
+		for (const p of st.expression.right.properties) {
+			if (p.type !== "Property" || p.computed) {
+				problems.push(`module.exports: unsupported property ${text.slice(p.start, p.end).slice(0, 60)}`);
+				continue;
+			}
+			const key = p.key.type === "Identifier" ? p.key.name : String(p.key.value);
+			if (p.shorthand) list.push([key, key]);
+			else if (!p.method && p.value.type === "Identifier") list.push([p.value.name, key]);
+			else if (p.method || p.kind !== "init") {
+				// method shorthand / getter: keep the exact source inside a one-property object
+				consts.push(`const __export_${key} = ({ ${text.slice(p.start, p.end)} }).${key};`);
+				list.push([`__export_${key}`, key]);
+			} else {
+				// key: expression (e.g. texture: assets.texture, save: async (...) => {...})
+				consts.push(`const __export_${key} = ${text.slice(p.value.start, p.value.end)};`);
+				list.push([`__export_${key}`, key]);
+			}
+		}
+		const named = list.map(([local, key]) => (local === key ? key : `${local} as ${key}`));
+		// default export too: other modules do `const x = require("./y")` -> `import x from "./y.js"`
+		const defaults = list.map(([local, key]) => (local === key ? key : `${key}: ${local}`));
+		const out = `${consts.join("\n")}${consts.length ? "\n" : ""}export { ${named.join(", ")} };\nexport default { ${defaults.join(", ")} };\n`;
+		text = text.slice(0, st.start) + out + text.slice(st.end);
+	}
+}
+text = text.replace(/^module\.exports = (\w+);?\s*$/m, "export default $1;\n");
+
+for (const [i, line] of text.split("\n").entries()) {
+	if (/\brequire\(/.test(line)) problems.push(`${i + 1}: require left: ${line.trim()}`);
+	if (/\bmodule\.exports\b|\bexports\.\w+\s*=/.test(line)) problems.push(`${i + 1}: exports left: ${line.trim()}`);
+	if (/\b__dirname\b|\b__filename\b|process\.(env|platform|argv)/.test(line)) problems.push(`${i + 1}: node global: ${line.trim()}`);
+}
+fs.mkdirSync(dst.replace(/[\\/][^\\/]+$/, ""), { recursive: true });
+fs.writeFileSync(dst, `// Ported from LS Tools desktop: ${src.replace(/\\/g, "/").split("/src/").pop()} (mechanical CJS -> ESM)\n` + text);
+console.log(`${dst}: ${problems.length ? problems.length + " to check" : "ok"}`);
+for (const p of problems) console.log("  " + p);