From c64ef1c13bd7e99789eaeec1b785927a02ab0522 Mon Sep 17 00:00:00 2001
From: Patrick Heng <hengpatrick.pro@gmail.com>
Date: Mon, 13 Feb 2017 01:38:42 +0100
Subject: [PATCH] fix: onChange throw error handler sooner in instructions

---
 src/index.js | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/index.js b/src/index.js
index ceb999e..24d153d 100644
--- a/src/index.js
+++ b/src/index.js
@@ -112,6 +112,10 @@ class State {
    * @param {function} callback Callback
    */
   onChange (query, callback) {
+    if (typeof callback !== 'function') {
+      throw new TypeError('Signal.onChange() : Second argument must be a Function')
+    }
+
     const { container, containerId, splittedQuery } = this._parseStateQuery(query)
 
     let signalId = containerId
@@ -124,10 +128,6 @@ class State {
       container.signals[signalId] = new Signal()
     }
 
-    if (typeof callback !== 'function') {
-      throw new TypeError('Signal.onChange() : Second argument must be a Function')
-    }
-
     container.signals[signalId].add(callback)
   }