add debug(err) support. Closes #46

debug.js

@@ -17,6 +17,8 @@ function debug(name) {
   if (!debug.enabled(name)) return function(){};
 
   return function(fmt){
+    fmt = coerce(fmt);
+
     var curr = new Date;
     var ms = curr - (debug[name] || curr);
     debug[name] = curr;
@@ -119,6 +121,15 @@ debug.enabled = function(name) {
   return false;
 };
 
+/**
+ * Coerce `val`.
+ */
+
+function coerce(val) {
+  if (val instanceof Error) return val.stack;
+  return val;
+}
+
 // persist
 
 if (window.localStorage) debug.enable(localStorage.debug);

example/worker.js

@@ -19,4 +19,8 @@ function workb() {
   setTimeout(workb, Math.random() * 2000);
 }
 
-workb();
+workb();
+
+setTimeout(function(){
+  b(new Error('fail'));
+}, 5000);

lib/debug.js

@@ -108,6 +108,8 @@ function debug(name) {
   var c = color();
 
   function colored(fmt) {
+    fmt = coerce(fmt);
+
     var curr = new Date;
     var ms = curr - (prev[name] || curr);
     prev[name] = curr;
@@ -121,6 +123,8 @@ function debug(name) {
   }
 
   function plain(fmt) {
+    fmt = coerce(fmt);
+
     fmt = new Date().toUTCString()
       + ' ' + name + ' ' + fmt;
     console.error.apply(this, arguments);
@@ -132,3 +136,12 @@ function debug(name) {
     ? colored
     : plain;
 }
+
+/**
+ * Coerce `val`.
+ */
+
+function coerce(val) {
+  if (val instanceof Error) return val.stack;
+  return val;
+}