1 files changed, 28 insertions, 0 deletions
diff --git a/browser/components/payments/res/mixins/HandleEventMixin.js b/browser/components/payments/res/mixins/HandleEventMixin.js
new file mode 100644
index 0000000000..8d09ac2207
--- /dev/null
+++ b/browser/components/payments/res/mixins/HandleEventMixin.js
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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * A mixin to forward events to on* methods if defined.
+ *
+ * @param {string} superclass The class to extend.
+ * @returns {class}
+ */
+export default function HandleEventMixin(superclass) {
+  return class HandleEvent extends superclass {
+    handleEvent(evt) {
+      function capitalize(str) {
+        return str.charAt(0).toUpperCase() + str.slice(1);
+      }
+      if (super.handleEvent) {
+        super.handleEvent(evt);
+      }
+      // Check whether event name is a defined function in object.
+      let fn = "on" + capitalize(evt.type);
+      if (this[fn] && typeof this[fn] === "function") {
+        return this[fn](evt);
+      }
+      return null;
+    }
+  };
+}