Alleviate weird issue with duplicate handling

This is still a bug, albeit one less glaring than before. This module is
in dire need of a full rewrite...

index.js

@@ -524,18 +524,17 @@ function getOpts(input, optdef = null, config = {}){
 		else{
 			const {names} = option;
 
-			// Ascertain if this option's being duplicated
-			if(result.options[ names[0] ])
-				value = resolveDuplicate(option, value);
-
-
-			option.names.forEach(name => {
+			for(let name of names){
 
 				// Decide whether to camelCase this option name
 				name = formatName(name, noCamelCase);
 
+				// Ascertain if this option's being duplicated
+				if(result.options[name])
+					resolveDuplicate(option, name, value);
+
 				result.options[name] = value;
-			});
+			}
 		}
 	}