Add collapsing kanban buckets

src/helpers/saveCollapsedBucketState.js

@@ -0,0 +1,30 @@
+const key = 'collapsedBuckets'
+
+const getAllState = () => {
+	const saved = localStorage.getItem(key)
+	if (saved === null) {
+		return {}
+	}
+
+	return JSON.parse(saved)
+}
+
+export const saveCollapsedBucketState = (listId, collapsedBuckets) => {
+	const state = getAllState()
+	state[listId] = collapsedBuckets
+	for (const bucketId in state[listId]) {
+		if (!state[listId][bucketId]) {
+			delete state[listId][bucketId]
+		}
+	}
+	localStorage.setItem(key, JSON.stringify(state))
+}
+
+export const getCollapsedBucketState = listId => {
+	const state = getAllState()
+	if (typeof state[listId] !== 'undefined') {
+		return state[listId]
+	}
+
+	return {}
+}