Add memoized insert method

Author: fritz-c

src/utils/memoized-tree-data-utils.js

@@ -0,0 +1,39 @@
+import { insertNode } from './tree-data-utils';
+
+let memoizedInsertArgsArray = [];
+let memoizedInsertKeysArray = [];
+let memoizedInsertResult    = null;
+
+/**
+ * Insert a node into the tree at the given depth, after the minimum index
+ *
+ * @param {!Object[]} treeData - Tree data
+ * @param {!number} depth - The depth to insert the node at (the first level of the array being depth 0)
+ * @param {!number} minimumTreeIndex - The lowest possible treeIndex to insert the node at
+ * @param {!Object} newNode - The node to insert into the tree
+ * @param {boolean=} ignoreCollapsed - Ignore children of nodes without `expanded` set to `true`
+ * @param {boolean=} expandParent - If true, expands the parent of the inserted node
+ * @param {!function} getNodeKey - Function to get the key from the nodeData and tree index
+ *
+ * @return {Object} result
+ * @return {Object[]} result.treeData - The tree data with the node added
+ * @return {number} result.treeIndex - The tree index at which the node was inserted
+ * @return {number[]|string[]} result.path - Array of keys leading to the node location after insertion
+ */
+export function memoizedInsertNode(args) {
+    const keysArray = Object.keys(args).sort();
+    const argsArray = keysArray.map(key => args[key]);
+
+    // If the arguments for the last insert operation are different than this time,
+    // recalculate the result
+    if (argsArray.length !== memoizedInsertArgsArray.length ||
+        argsArray.some((arg, index) => arg !== memoizedInsertArgsArray[index]) ||
+        keysArray.some((key, index) => key !== memoizedInsertKeysArray[index])
+    ) {
+        memoizedInsertArgsArray = argsArray;
+        memoizedInsertKeysArray = keysArray;
+        memoizedInsertResult    = insertNode(args);
+    }
+
+    return memoizedInsertResult;
+}

src/utils/memoized-tree-data-utils.test.js

@@ -0,0 +1,23 @@
+import {
+    insertNode,
+} from './tree-data-utils';
+
+import {
+    memoizedInsertNode,
+} from './memoized-tree-data-utils';
+
+describe('insertNode', () => {
+    it('should handle empty data', () => {
+        const params = {
+            treeData: [],
+            depth: 0,
+            minimumTreeIndex: 0,
+            newNode: {},
+            getNodeKey: ({ treeIndex }) => treeIndex,
+        };
+
+        expect(insertNode(params) === insertNode(params)).toEqual(false);
+        expect(memoizedInsertNode(params) === memoizedInsertNode(params)).toEqual(true);
+        expect(memoizedInsertNode(params) === memoizedInsertNode({...params, treeData: [{}]})).toEqual(false);
+    });
+});