diff --git a/src/Client.ts b/src/Client.ts
index dd1b640..81c0fa9 100644
--- a/src/Client.ts
+++ b/src/Client.ts
@@ -138,7 +138,7 @@ export class Client {
                 const capsToChange = (message.params[1].indexOf(' ') === -1) ? [message.params[1]] : message.params[1].split(' ');
                 const capsEnabled: string[] = [];
                 capsToChange.forEach(cap => {
-                    if (this.allCaps.get(cap)) {
+                    if (this.allCaps.has(cap)) {
                         this.enabledCaps.set(cap, '');
                         capsEnabled.push(cap);
                     }