refactor: use assert, fix: respect to express settings.views, close #16

src/util/assert.js

@@ -0,0 +1,13 @@
+const AssertionError = require('./error.js').AssertionError;
+
+function assert(predicate, message) {
+    if (!predicate) {
+        if (message instanceof Error) {
+            throw message;
+        }
+        var message = message || `expect ${predicate} to be true`;
+        throw new AssertionError(message);
+    }
+}
+
+module.exports = assert;