[Switch Access] Simplify node construction

All calls to connectChildren were immediately followed by a call to
setChildren, so I combined them, along with several other readability
changes.

This change is a pure refactor.

Bug: None
Change-Id: If340c812127d95412939977a12f247203da07d86
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1902516
Commit-Queue: Anastasia Helfinstein <anastasi@google.com>
Reviewed-by: Chris Hall <chrishall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714970}

chrome/browser/resources/chromeos/switch_access/nodes/group_node.js

@@ -84,11 +84,8 @@ class GroupNode extends SAChildNode {
       children.push(child);
     }
 
-    const backButton = new BackButtonNode(root);
-    children.push(backButton);
-
-    SARootNode.connectChildren(children);
-    root.setChildren(children);
+    children.push(new BackButtonNode(root));
+    root.children = children;
 
     return root;
   }

chrome/browser/resources/chromeos/switch_access/nodes/keyboard_node.js

@@ -57,15 +57,15 @@ class KeyboardNode extends NodeWrapper {
     }
 
     const root = new RootNodeWrapper(node);
-    KeyboardNode.buildHelper(root);
+    KeyboardNode.findAndSetChildren(root);
     return root;
   }
 
   /**
-   * Builds a tree of KeyboardNodes.
+   * Helper function to connect tree elements, given the root node.
    * @param {!RootNodeWrapper} root
    */
-  static buildHelper(root) {
+  static findAndSetChildren(root) {
     const childConstructor = (node) => new KeyboardNode(node, root);
 
     /** @type {!Array<!chrome.automation.AutomationNode>} */
@@ -75,11 +75,8 @@ class KeyboardNode extends NodeWrapper {
       children = GroupNode.separateByRow(children);
     }
 
-    const backButton = new BackButtonNode(root);
-    children.push(backButton);
-
-    SARootNode.connectChildren(children);
-    root.setChildren(children);
+    children.push(new BackButtonNode(root));
+    root.children = children;
   }
 }
 
@@ -126,7 +123,7 @@ class KeyboardRootNode extends RootNodeWrapper {
 
     const root = new KeyboardRootNode(keyboard);
     root.onEnter_();
-    KeyboardNode.buildHelper(root);
+    KeyboardNode.findAndSetChildren(root);
     return root;
   }
 }

chrome/browser/resources/chromeos/switch_access/nodes/node_wrapper.js

@@ -208,18 +208,18 @@ class RootNodeWrapper extends SARootNode {
     const root = new RootNodeWrapper(rootNode);
     const childConstructor = (node) => new NodeWrapper(node, root);
 
-    RootNodeWrapper.buildHelper(root, childConstructor);
+    RootNodeWrapper.findAndSetChildren(root, childConstructor);
     return root;
   }
 
   /**
-   * Helper function to connect tree elements, given constructors for the root
-   * and child types.
+   * Helper function to connect tree elements, given the root node and a
+   * constructor for the child type.
    * @param {!RootNodeWrapper} root
    * @param {function(!AutomationNode): !SAChildNode} childConstructor
    *     Constructs a child node from an automation node.
    */
-  static buildHelper(root, childConstructor) {
+  static findAndSetChildren(root, childConstructor) {
     const interestingChildren = RootNodeWrapper.getInterestingChildren(root);
 
     if (interestingChildren.length < 1) {
@@ -228,12 +228,8 @@ class RootNodeWrapper extends SARootNode {
           'Root node must have at least 1 interesting child.');
     }
     let children = interestingChildren.map(childConstructor);
-
-    const backButton = new BackButtonNode(root);
-    children.push(backButton);
-
-    SARootNode.connectChildren(children);
-    root.setChildren(children);
+    children.push(new BackButtonNode(root));
+    root.children = children;
   }
 
   /**
@@ -252,9 +248,7 @@ class RootNodeWrapper extends SARootNode {
 
     const childConstructor = (autoNode) => new NodeWrapper(autoNode, root);
     let children = interestingChildren.map(childConstructor);
-
-    SARootNode.connectChildren(children);
-    root.setChildren(children);
+    root.children = children;
 
     return root;
   }

chrome/browser/resources/chromeos/switch_access/nodes/switch_access_node.js

@@ -21,20 +21,14 @@ class SAChildNode {
     this.next_ = null;
   }
 
-  /**
-   * @param {!SAChildNode} previous
-   * @protected
-   */
-  setPrevious_(previous) {
-    this.previous_ = previous;
+  /** @param {!SAChildNode} newVal */
+  set previous(newVal) {
+    this.previous_ = newVal;
   }
 
-  /**
-   * @param {!SAChildNode} next
-   * @protected
-   */
-  setNext_(next) {
-    this.next_ = next;
+  /** @param {!SAChildNode} newVal */
+  set next(newVal) {
+    this.next_ = newVal;
   }
 
   /**
@@ -136,12 +130,12 @@ class SAChildNode {
   asRootNode() {}
 
   /**
-   * Called when a node becomes the primary highlighted node.
+   * Called when this node becomes the primary highlighted node.
    */
   onFocus() {}
 
   /**
-   * Called when a node stops being the primary highlighted node.
+   * Called when this node stops being the primary highlighted node.
    */
   onUnfocus() {}
 
@@ -187,9 +181,10 @@ class SARootNode {
     this.children_ = [];
   }
 
-  /** @param {!Array<!SAChildNode>} children */
-  setChildren(children) {
-    this.children_ = children;
+  /** @param {!Array<!SAChildNode>} newVal */
+  set children(newVal) {
+    this.children_ = newVal;
+    this.connectChildren_();
   }
 
   /**
@@ -302,21 +297,21 @@ class SARootNode {
 
   /**
    * Helper function to connect children.
-   * @param {!Array<!SAChildNode>} children
+   * @private
    */
-  static connectChildren(children) {
-    if (children.length < 1) {
+  connectChildren_() {
+    if (this.children_.length < 1) {
       throw SwitchAccess.error(
           SAConstants.ErrorType.NO_CHILDREN,
           'Root node must have at least 1 interesting child.');
     }
 
-    let previous = children[children.length - 1];
+    let previous = this.children_[this.children_.length - 1];
 
-    for (let i = 0; i < children.length; i++) {
-      let current = children[i];
-      previous.setNext_(current);
-      current.setPrevious_(previous);
+    for (let i = 0; i < this.children_.length; i++) {
+      let current = this.children_[i];
+      previous.next = current;
+      current.previous = previous;
 
       previous = current;
     }

chrome/browser/resources/chromeos/switch_access/nodes/system_menu_node.js

@@ -29,7 +29,7 @@ class SystemMenuRootNode extends RootNodeWrapper {
     const root = new SystemMenuRootNode(menuNode);
     const childConstructor = (node) => new NodeWrapper(node, root);
 
-    RootNodeWrapper.buildHelper(root, childConstructor);
+    RootNodeWrapper.findAndSetChildren(root, childConstructor);
     return root;
   }
 }