From 31a95e60692cec6d1939c01645da04c0f49b4f10 Mon Sep 17 00:00:00 2001
From: Ewan Roycroft <ewan.roycroft@bbc.co.uk>
Date: Tue, 31 May 2022 15:45:30 +0100
Subject: [PATCH 1/3] insertTree: Maintain active children if requested

If the maintainActiveChildren option is set, any activeChildren set in
the subTreeRootNodeConfig will be assigned.
---
 src/index.ts      | 10 +++++++++-
 src/interfaces.ts |  2 ++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/index.ts b/src/index.ts
index 0f17557..5aca8e2 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1036,7 +1036,7 @@ export class Lrud {
    * @param {boolean} [options.maintainIndex] - if true, and new tree is replacing an existing branch of the tree,
    *                                            maintain the original branches relative index; default: true
    */
-  insertTree (subTreeRootNodeConfig: NodeConfig, options: InsertTreeOptions = { maintainIndex: true }): void {
+  insertTree (subTreeRootNodeConfig: NodeConfig, options: InsertTreeOptions = { maintainIndex: true, maintainActiveChildren: false }): void {
     if (!subTreeRootNodeConfig) {
       return
     }
@@ -1051,6 +1051,14 @@ export class Lrud {
     }
 
     this.registerTree(subTreeRootNodeConfig)
+
+    if (options.maintainActiveChildren) {
+      traverseNodeSubtree(subTreeRootNodeConfig, traversedNodeConfig => {
+        if (traversedNodeConfig.activeChild) {
+          this.getNode(traversedNodeConfig.id).activeChild = this.getNode(traversedNodeConfig.activeChild)
+        }
+      })
+    }
   }
 
   /**
diff --git a/src/interfaces.ts b/src/interfaces.ts
index b41e7c9..b67d0d5 100644
--- a/src/interfaces.ts
+++ b/src/interfaces.ts
@@ -60,6 +60,7 @@ export interface Node extends Tree<Node> {
 export interface NodeConfig extends Tree<NodeConfig>, Omit<Node, 'id'|'parent'|'activeChild'|'children'|'overrides'|'overrideSources'> {
   id?: NodeId
   parent?: NodeId
+  activeChild?: NodeId
 }
 
 export type NodesBag = { [id in NodeId]: Node }
@@ -75,6 +76,7 @@ export interface HandleKeyEventOptions {
 
 export interface InsertTreeOptions {
   maintainIndex?: boolean
+  maintainActiveChildren?: boolean
 }
 
 export interface UnregisterNodeOptions {

From 6c376972b862f69c5f65ab1db12504af730e5e81 Mon Sep 17 00:00:00 2001
From: Ewan Roycroft <ewan.roycroft@bbc.co.uk>
Date: Tue, 31 May 2022 15:56:22 +0100
Subject: [PATCH 2/3] NodeConfig: Allow activeChild to be of type Node

---
 src/index.ts      | 5 ++++-
 src/interfaces.ts | 2 +-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index 5aca8e2..8b322fa 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1055,7 +1055,10 @@ export class Lrud {
     if (options.maintainActiveChildren) {
       traverseNodeSubtree(subTreeRootNodeConfig, traversedNodeConfig => {
         if (traversedNodeConfig.activeChild) {
-          this.getNode(traversedNodeConfig.id).activeChild = this.getNode(traversedNodeConfig.activeChild)
+          this.getNode(traversedNodeConfig.id).activeChild = this.getNode(
+            typeof traversedNodeConfig.activeChild === 'string'
+              ? traversedNodeConfig.activeChild
+              : traversedNodeConfig.activeChild.id)
         }
       })
     }
diff --git a/src/interfaces.ts b/src/interfaces.ts
index b67d0d5..fb02cf8 100644
--- a/src/interfaces.ts
+++ b/src/interfaces.ts
@@ -60,7 +60,7 @@ export interface Node extends Tree<Node> {
 export interface NodeConfig extends Tree<NodeConfig>, Omit<Node, 'id'|'parent'|'activeChild'|'children'|'overrides'|'overrideSources'> {
   id?: NodeId
   parent?: NodeId
-  activeChild?: NodeId
+  activeChild?: NodeId | Node
 }
 
 export type NodesBag = { [id in NodeId]: Node }

From 60707e489c55f228d62f1fb6d554d96b217aec3e Mon Sep 17 00:00:00 2001
From: Ewan Roycroft <ewan.roycroft@bbc.co.uk>
Date: Tue, 31 May 2022 16:47:16 +0100
Subject: [PATCH 3/3] Add tests for insertTree/maintainActiveChildren

---
 src/insert-tree.test.js | 63 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/src/insert-tree.test.js b/src/insert-tree.test.js
index 8ce0fec..114c4e8 100644
--- a/src/insert-tree.test.js
+++ b/src/insert-tree.test.js
@@ -233,4 +233,67 @@ describe('insertTree()', () => {
 
     expect(() => navigation.insertTree(undefined)).not.toThrow()
   })
+
+  test('should not maintain active children if maintainActiveChildren not enabled', () => {
+    const navigation = new Lrud()
+      .registerNode('root')
+      .registerNode('a')
+      .registerNode('b')
+
+    const subTree = {
+      id: 'c',
+      orientation: 'vertical',
+      activeChild: 'c_1',
+      children: [
+        { id: 'c_1', isFocusable: true },
+        { id: 'c_2', isFocusable: true }
+      ]
+    }
+
+    navigation.insertTree(subTree)
+
+    expect(navigation.getNode('c').activeChild).not.toBeDefined()
+  })
+
+  test('should maintain active children if maintainActiveChildren enabled', () => {
+    const navigation = new Lrud()
+      .registerNode('root')
+      .registerNode('a')
+      .registerNode('b')
+
+    const subTree = {
+      id: 'c',
+      orientation: 'vertical',
+      activeChild: 'c_1',
+      children: [
+        { id: 'c_1', isFocusable: true },
+        { id: 'c_2', isFocusable: true }
+      ]
+    }
+
+    navigation.insertTree(subTree, { maintainActiveChildren: true })
+
+    expect(navigation.getNode('c').activeChild.id).toEqual('c_1')
+  })
+
+  test('should maintain active children if Node supplied', () => {
+    const navigation = new Lrud()
+      .registerNode('root')
+      .registerNode('a')
+      .registerNode('b')
+
+    const subTree = {
+      id: 'c',
+      orientation: 'vertical',
+      activeChild: { id: 'c_1' },
+      children: [
+        { id: 'c_1', isFocusable: true },
+        { id: 'c_2', isFocusable: true }
+      ]
+    }
+
+    navigation.insertTree(subTree, { maintainActiveChildren: true })
+
+    expect(navigation.getNode('c').activeChild.id).toEqual('c_1')
+  })
 })