improved error reporting

not entirely sure about the respective origins (Babel vs. Rollup), but
this seems to work

Author: FND

lib/util.js

@@ -16,11 +16,10 @@ exports.generateError = err => {
 	let msg = `ERROR: ${err}`;
 	console.error(`✗ ${msg}`);
 	if(err.code) { // Rollup-augmented exception; emit in full detail
-		let { codeFrame } = err; // excerpt, provided by Babel
-		if(codeFrame) {
-			delete err.codeFrame;
-			console.error(err);
-			console.error(`\n${codeFrame}\n`);
+		if(err.codeFrame) { // excerpt, provided by Babel
+			reportCodeFrame(err, "codeFrame");
+		} else if(err.frame) { // excerpt, provided by Rollup
+			reportCodeFrame(err, "frame");
 		} else {
 			console.error(err);
 		}
@@ -32,3 +31,10 @@ exports.generateError = err => {
 	}
 	return `${NOTIFY}("${msg.replace(/"/g, '\\"')}");`;
 };
+
+function reportCodeFrame(err, prop) {
+	let frame = err[prop];
+	delete err[prop];
+	console.error(err);
+	console.error(`\n${frame}\n`);
+}