Merge pull request #321 from cujojs/safe-json-stringify-unhandled-rejections

Better error messages on unhanlded rejections, guard JSON.stringify

Author: briancavalier

lib/decorators/unhandledRejection.js

@@ -66,12 +66,20 @@ define(function(require) {
 		} else {
 			s = String(e);
 			if(s === '[object Object]' && typeof JSON !== 'undefined') {
-				s = JSON.stringify(e);
+				s = tryStringify(e, s);
 			}
 		}
 
 		return e instanceof Error ? s : s + ' (WARNING: non-Error used)';
+	}
 
+	function tryStringify(e, defaultValue) {
+		try {
+			return JSON.stringify(e);
+		} catch(e) {
+			// Ignore. Cannot JSON.stringify e, stick with String(e)
+			return defaultValue;
+		}
 	}
 
 	function noop() {}

test/unhandledRejection-test.js

@@ -0,0 +1,19 @@
+var buster = typeof window !== 'undefined' ? window.buster : require('buster');
+var unhandledRejection = require('../lib/decorators/unhandledRejection');
+
+buster.testCase('unhandledRejection', {
+
+	'should not fail if JSON.stringify throws': function(done) {
+		var fixture = unhandledRejection({}, function(f) {
+			setTimeout(function() {
+				buster.refute.exception(f);
+				done();
+			});
+		});
+		var circular = {};
+		circular.self = circular;
+
+		fixture.onPotentiallyUnhandledRejection({ handled: false, value: circular });
+	}
+
+});