Tests for toggleFolderOpenState();

frontend/scratch/__tests__/actions_test.ts

@@ -0,0 +1,65 @@
+import { FolderNode } from "../constants";
+import { ingest } from "../data_transfer";
+import { findFolder, toggleFolderOpenState } from "../actions";
+import { times, sample } from "lodash";
+// Folder structure used in tests:
+// ├─ One
+// ├─ Two
+// │  └─ Three
+// ├─ Four
+// │  └─ Five
+// ├─ Six
+// │  └─ Seven
+// │     ├─ Eight
+// │     └─ Nine
+// ├─ Ten
+// │  ├─ Eleven
+// │  └─ Twelve
+// │     └─ Thirteen
+// └─ Fourteen
+//    ├─ Fifteen
+//    └─ Sixteen
+//       ├─ Seventeen
+//       └─ Eighteen
+const FOLDERS: FolderNode[] = [
+  { id: 1, parent_id: undefined, color: "blue", name: "One" },
+  { id: 2, parent_id: undefined, color: "blue", name: "Two" },
+  { id: 3, parent_id: 2, color: "blue", name: "Three" },
+  { id: 4, parent_id: undefined, color: "blue", name: "Four" },
+  { id: 5, parent_id: 4, color: "blue", name: "Five" },
+  { id: 6, parent_id: undefined, color: "blue", name: "Six" },
+  { id: 7, parent_id: 6, color: "blue", name: "Seven" },
+  { id: 8, parent_id: 7, color: "blue", name: "Eight" },
+  { id: 9, parent_id: 7, color: "blue", name: "Nine" },
+  { id: 10, parent_id: undefined, color: "blue", name: "Ten" },
+  { id: 11, parent_id: 10, color: "blue", name: "Eleven" },
+  { id: 12, parent_id: 10, color: "blue", name: "Twelve" },
+  { id: 13, parent_id: 12, color: "blue", name: "Thirteen" },
+  { id: 14, parent_id: undefined, color: "blue", name: "Fourteen" },
+  { id: 15, parent_id: 14, color: "blue", name: "Fifteen" },
+  { id: 16, parent_id: 14, color: "blue", name: "Sixteen" },
+  { id: 17, parent_id: 16, color: "blue", name: "Seventeen" },
+  { id: 18, parent_id: 16, color: "blue", name: "Eighteen" }
+];
+
+const GRAPH = ingest(FOLDERS);
+
+describe("toggleFolderOpenState", () => {
+  it("toggles the `open` value of a folder", () => {
+    times(10, async () => {
+      const node = sample(FOLDERS);
+      if (!node) {
+        throw new Error("Impossible");
+      }
+      const { id } = node;
+      const before = findFolder(GRAPH, id);
+      const nextGraph = await toggleFolderOpenState(GRAPH, id);
+      const after = findFolder(nextGraph, id);
+      if (before && after) {
+        expect(after.open).toEqual(!before.open);
+      } else {
+        fail("Could not find ID.");
+      }
+    });
+  });
+});

frontend/scratch/actions.ts

@@ -1,14 +1,44 @@
 import {
-  RootFolderNode as Tree
+  RootFolderNode as Tree,
+  FolderUnion
 } from "./constants";
+import { cloneAndClimb } from "./climb";
 
-export const toggleFolderState = (_: Tree, _id: number) => {
-  return Promise.resolve(_);
+export const findFolder = (tree: Tree, id: number) => {
+  let result: FolderUnion | undefined;
+  cloneAndClimb(tree, (node, halt) => {
+    if (node.id === id) {
+      result = node;
+      halt();
+    }
+  });
+  return result;
 };
-export const expandAll = (_: Tree) => Promise.reject("WIP");
-export const collapseAll = (_: Tree) => Promise.reject("WIP");
-export const setFolderColor = (_: Tree) => Promise.reject("WIP");
-export const setFolderName = (_: Tree) => Promise.reject("WIP");
+
+export const toggleFolderOpenState = (tree: Tree, id: number) => {
+  return Promise.resolve(cloneAndClimb(tree, (node, halt) => {
+    if (node.id === id) {
+      node.open = !node.open;
+      halt();
+    }
+  }));
+};
+
+export const expandAll = (tree: Tree) => {
+  return Promise.resolve(cloneAndClimb(tree, (node) => {
+    node.open = true;
+  }));
+};
+
+export const collapseAll = (tree: Tree) => {
+  return Promise.resolve(cloneAndClimb(tree, (node) => {
+    node.open = false;
+  }));
+};
+
+export const setFolderColor = (_: Tree, _id: number) => Promise.reject("WIP");
+export const setFolderName =
+  (_: Tree, _id: number, _name: string) => Promise.reject("WIP");
 export const createFolder = (_: Tree) => Promise.reject("WIP");
 export const deleteFolder = (_: Tree) => Promise.reject("WIP");
 export const moveFolderItem = (_: Tree) => Promise.reject("WIP");

frontend/scratch/climb.ts

@@ -1,18 +1,21 @@
-import { RootFolderNode, FolderUnion } from "./constants";
+import { RootFolderNode, FolderUnion, FolderNodeMedial, FolderNodeInitial } from "./constants";
+import { defensiveClone } from "../util";
 
 interface TreeClimberState {
   active: boolean;
 }
 
 interface VisitorProps {
-  node: FolderUnion;
+  node: FolderNodeInitial | FolderNodeMedial;
   callback: TreeClimber;
   halt: Halt;
   state: TreeClimberState;
 }
 
 type Halt = () => void;
-type TreeClimber = (t: FolderUnion, halt: Function) => void;
+type TreeClimber = (t: FolderUnion,
+  /** Calling this function stops tree climb from continuing. */
+  halt: Function) => void;
 
 function visit(p: VisitorProps) {
   const { node, callback, halt } = p;
@@ -30,6 +33,7 @@ function visit(p: VisitorProps) {
   });
 }
 
+/** Recursively climb a directory structure. */
 export const climb = (t: RootFolderNode, callback: TreeClimber) => {
   const state: TreeClimberState = { active: true };
   const halt = () => { state.active = false; };
@@ -37,5 +41,11 @@ export const climb = (t: RootFolderNode, callback: TreeClimber) => {
     const props = { node, callback, halt, state };
     state.active && visit(props);
   });
-  return [];
+  return t;
+};
+
+/** TODO: Create strategies for non-destructively
+ * transforming a RootFolderNode. */
+export const cloneAndClimb = (t: RootFolderNode, callback: TreeClimber) => {
+  return climb(defensiveClone(t), callback);
 };

frontend/scratch/data_transfer.ts

@@ -13,13 +13,14 @@ const setDefaultParentId = (input: FolderNode): Required<FolderNode> => {
   return { ...input, parent_id: input.parent_id || -1 };
 };
 
-const addToIndex =
-  (accumulator: FoldersIndexedByParentId, item: Required<FolderNode>) => {
-    const key = item.parent_id;
-    const value = accumulator[key] || [];
-
-    return { ...accumulator, [key]: [...value, item] };
-  };
+type AddToIndex = (a: FoldersIndexedByParentId, i: Required<FolderNode>) =>
+  Record<number, FolderNode[] | undefined>;
+const addToIndex: AddToIndex = (accumulator, item) => {
+  const key = item.parent_id;
+  const lastValue: FolderNode[] = accumulator[key] || [];
+  const nextValue: FolderNode[] = [...lastValue, item];
+  return { ...accumulator, [key]: nextValue };
+};
 
 const emptyIndex: FoldersIndexedByParentId = {};
 
@@ -42,7 +43,7 @@ export function ingest(input: FolderNode[]): RootFolderNode {
     content: []
   });
 
-  const initial = (x: FolderNode) => (index[x.id].length) ?
+  const initial = (x: FolderNode) => (index[x.id] || []).length ?
     medial(x) : terminal(x);
 
   childrenOf(-1).map((root) => {