diff --git a/src/index.js b/src/index.js
index a95771d..b245c2d 100644
--- a/src/index.js
+++ b/src/index.js
@@ -39,6 +39,9 @@ module.exports.process = async (env, tasks) => {
         if(!(type in types))
             throw `${type} is not a supported build task type`;
 
+        if(!(type in tasks))
+            continue;
+
         const typeTasks = tasks[type];
         if(!Array.isArray(typeTasks))
             throw 'children of the tasks object must be arrays';