add useful stack traces

lib/makeerror.js

@@ -56,6 +56,24 @@ function makeError(name, defaultMessage, defaultData) {
     } else {
       this.message = defaultMessage(this.data)
     }
+
+    var er = new Error()
+    this.stack = er.stack
+    if (this.stack) {
+      // remove TWO stack level:
+      if (typeof Components !== 'undefined') {
+        // Mozilla:
+        this.stack = this.stack.substring(this.stack.indexOf('\n') + 2)
+      } else if (typeof chrome !== 'undefined' || typeof process !== 'undefined') {
+        // Google Chrome/Node.js:
+        this.stack = this.stack.replace(/\n[^\n]*/, '')
+        this.stack = this.stack.replace(/\n[^\n]*/, '')
+        this.stack = this.name + this.stack.substring(5)
+      }
+    }
+
+    if ('fileName' in er) this.fileName = er.fileName
+    if ('lineNumber' in er) this.lineNumber = er.lineNumber
   }
 
   CustomError.prototype = defaultData.proto || new BaseError()

package.json

@@ -1,7 +1,7 @@
 {
   "name": "makeerror",
   "description": "A library to make errors.",
-  "version": "1.0.5",
+  "version": "1.0.6",
   "author": "Naitik Shah <n@daaku.org>",
   "main": "lib/makeerror",
   "repository": {

test/makeerror-tests.js

@@ -140,5 +140,12 @@ exports['proto must be created via makeError'] = function(beforeExit) {
       makeError('Child', '', { proto: new Error() })
     },
     /created via makeError/
-  );
+  )
+}
+
+exports['stack trace'] = function(beforeExit) {
+  var name = 'MyError'
+    , MyError = makeError(name)
+    , er = MyError()
+  assert.match(er.stack, new RegExp(name + '\\n *at ' + __filename))
 }