Functional directives TS

app/assets/javascripts/directives/functional/lowercase.ts

@@ -0,0 +1,24 @@
+/* @ngInject */
+export function lowercase() {
+  return {
+    require: 'ngModel',
+    link: function (
+      scope: ng.IScope,
+      _: JQLite,
+      attrs: any,
+      ctrl: ng.IController
+    ) {
+      const lowercase = (inputValue: string) => {
+        if (inputValue === undefined) inputValue = '';
+        const lowercased = inputValue.toLowerCase();
+        if (lowercased !== inputValue) {
+          ctrl.$setViewValue(lowercased);
+          ctrl.$render();
+        }
+        return lowercased;
+      };
+      ctrl.$parsers.push(lowercase);
+      lowercase((scope as any)[attrs.ngModel]);
+    }
+  };
+}