1 files changed, 45 insertions, 0 deletions
diff --git a/lib/components.ts b/lib/components.ts
new file mode 100644
index 000000000..fb802ab47
--- /dev/null
+++ b/lib/components.ts
@@ -0,0 +1,45 @@
+/*
+ This file is part of TALER
+ (C) 2016 Inria
+
+ TALER is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+
+/**
+ * General helper components
+ * 
+ * @author Florian Dold
+ */
+
+export interface StateHolder<T> {
+  (): T;
+  (newState: T): void;
+}
+
+/**
+ * Component that doesn't hold its state in one object,
+ * but has multiple state holders.
+ */
+export abstract class ImplicitStateComponent<PropType> extends preact.Component<PropType, any> {
+  makeState<StateType>(initial: StateType): StateHolder<StateType> {
+    let state: StateType = initial;
+    return (s?: StateType): StateType => {
+      if (s !== undefined) {
+        state = s;
+        // In preact, this will always schedule a (debounced) redraw
+        this.setState({} as any);
+      }
+      return state;
+    };
+  }
+}
+\ No newline at end of file