Simple bind helper

This binds a function to a target before passing it along to another
component. It's normal to expect to get to use `this` within functions
on components and controllers, but (sans actions) that doesn't happen
automatically.

ui/app/helpers/bind.js

@@ -0,0 +1,17 @@
+import { helper } from '@ember/component/helper';
+import { assert } from '@ember/debug';
+
+/**
+ * bind
+ *
+ * Usage: {{bind this.function}}
+ *
+ * Returns a version of a function bound to the template target (e.g., component or controller)
+ */
+export function bind([func, target]) {
+  assert('A function is required as the first argument', typeof func === 'function');
+  assert('A context is required as the second argument', target);
+  return func.bind(target);
+}
+
+export default helper(bind);