created pending and failure module

scm-ui/src/modules/pending.js

@@ -0,0 +1,56 @@
+// @flow
+import type { Action } from "../types/Action";
+
+const PENDING_SUFFIX = "_PENDING";
+const RESET_PATTERN = /^(.*)_(SUCCESS|FAILURE|RESET)$/;
+
+function removeFromState(state: Object, identifier: string) {
+  let newState = {};
+  for (let childType in state) {
+    if (childType !== identifier) {
+      newState[childType] = state[childType];
+    }
+  }
+  return newState;
+}
+
+function extractIdentifierFromPending(action: Action) {
+  const type = action.type;
+  let identifier = type.substring(0, type.length - PENDING_SUFFIX.length);
+  if (action.itemId) {
+    identifier += "/" + action.itemId;
+  }
+  return identifier;
+}
+
+export default function reducer(state: Object = {}, action: Action): Object {
+  const type = action.type;
+  if (type.endsWith(PENDING_SUFFIX)) {
+    const identifier = extractIdentifierFromPending(action);
+    return {
+      ...state,
+      [identifier]: true
+    };
+  } else {
+    const matches = RESET_PATTERN.exec(type);
+    if (matches) {
+      return removeFromState(state, matches[1]);
+    }
+  }
+  return state;
+}
+
+export function isPending(
+  state: Object,
+  actionType: string,
+  itemId?: string | number
+) {
+  let type = actionType;
+  if (itemId) {
+    type += "/" + itemId;
+  }
+  if (state.pending && state.pending[type]) {
+    return true;
+  }
+  return false;
+}