Hierarchical event bubbling - 1

Reviewed By: @fkgozali

Differential Revision: D2469495

Libraries/CustomComponents/Navigator/Navigation/NavigationTreeNode.js

@@ -0,0 +1,91 @@
+/**
+ * Copyright (c) 2015, Facebook, Inc.  All rights reserved.
+ *
+ * @providesModule NavigationTreeNode
+ * @flow
+ * @typechecks
+ */
+
+'use strict';
+
+var invariant = require('invariant');
+var immutable = require('immutable');
+
+var {List} = immutable;
+
+/**
+ * Utility to build a tree of nodes.
+ * Note that this tree does not perform cyclic redundancy check
+ * while appending child node.
+ */
+class NavigationTreeNode {
+  __parent: ?NavigationTreeNode;
+
+  _children: List<NavigationTreeNode>;
+
+  _value: any;
+
+  constructor(value: any) {
+    this.__parent = null;
+    this._children = new List();
+    this._value = value;
+  }
+
+  getValue(): any {
+    return this._value;
+  }
+
+  getParent(): ?NavigationTreeNode {
+    return this.__parent;
+  }
+
+  getChildrenCount(): number {
+    return this._children.size;
+  }
+
+  getChildAt(index: number): ?NavigationTreeNode {
+    return index > -1 && index < this._children.size ?
+      this._children.get(index) :
+      null;
+  }
+
+  appendChild(child: NavigationTreeNode): void {
+    if (child.__parent) {
+      child.__parent.removeChild(child);
+    }
+    child.__parent = this;
+    this._children = this._children.push(child);
+  }
+
+  removeChild(child: NavigationTreeNode): void {
+    var index = this._children.indexOf(child);
+
+    invariant(
+      index > -1,
+      'The node to be removed is not a child of this node.'
+    );
+
+    child.__parent = null;
+
+    this._children = this._children.splice(index, 1);
+  }
+
+  indexOf(child: NavigationTreeNode): number {
+    return this._children.indexOf(child);
+  }
+
+  forEach(callback: Function, context: any): void {
+    this._children.forEach(callback, context);
+  }
+
+  map(callback: Function, context: any): Array<NavigationTreeNode> {
+    return this._children.map(callback, context).toJS();
+  }
+
+  some(callback: Function, context: any): boolean {
+    return this._children.some(callback, context);
+  }
+}
+
+
+module.exports = NavigationTreeNode;

Libraries/CustomComponents/Navigator/Navigation/__tests__/NavigationTreeNode-test.js

@@ -0,0 +1,111 @@
+/**
+ * Copyright (c) 2015, Facebook, Inc.  All rights reserved.
+ */
+
+'use strict';
+
+jest
+  .dontMock('Map')
+  .dontMock('NavigationTreeNode')
+  .dontMock('invariant')
+  .dontMock('immutable');
+
+var NavigationTreeNode = require('NavigationTreeNode');
+
+describe('NavigationTreeNode-test', () => {
+  it('should be empty', () => {
+    var node = new NavigationTreeNode();
+    expect(node.getValue()).toEqual(undefined);
+    expect(node.getParent()).toEqual(null);
+    expect(node.getChildrenCount()).toEqual(0);
+    expect(node.getChildAt(0)).toEqual(null);
+  });
+
+
+  it('should contain value', () => {
+    var node = new NavigationTreeNode(123);
+    expect(node.getValue()).toEqual(123);
+  });
+
+  it('should appendChild', () => {
+    var papa = new NavigationTreeNode('hedger');
+    var baby = new NavigationTreeNode('hedger jr');
+    papa.appendChild(baby);
+    expect(papa.getChildAt(0)).toEqual(baby);
+    expect(papa.getChildrenCount()).toEqual(1);
+    expect(baby.getParent()).toEqual(papa);
+  });
+
+  it('should removeChild', () => {
+    var papa = new NavigationTreeNode('Eddard Stark');
+    var baby = new NavigationTreeNode('Robb Stark');
+    papa.appendChild(baby);
+
+    papa.removeChild(baby);
+    expect(papa.getChildAt(0)).toEqual(null);
+    expect(papa.getChildrenCount()).toEqual(0);
+    expect(baby.getParent()).toEqual(null);
+  });
+
+  it('should not remove non-child', () => {
+    var papa = new NavigationTreeNode('dog');
+    var baby = new NavigationTreeNode('cat');
+    expect(papa.removeChild.bind(papa, baby)).toThrow();
+  });
+
+  it('should find child', () => {
+    var papa = new NavigationTreeNode('Eddard Stark');
+    var baby = new NavigationTreeNode('Robb Stark');
+
+    papa.appendChild(baby);
+    expect(papa.indexOf(baby)).toEqual(0);
+
+    papa.removeChild(baby);
+    expect(papa.indexOf(baby)).toEqual(-1);
+  });
+
+
+  it('should traverse each child', () => {
+    var parent = new NavigationTreeNode();
+    parent.appendChild(new NavigationTreeNode('a'));
+    parent.appendChild(new NavigationTreeNode('b'));
+    parent.appendChild(new NavigationTreeNode('c'));
+    var result = [];
+    parent.forEach((child, index) => {
+      result[index] = child.getValue();
+    });
+
+    expect(result).toEqual(['a', 'b', 'c']);
+  });
+
+  it('should map children', () => {
+    var parent = new NavigationTreeNode();
+    parent.appendChild(new NavigationTreeNode('a'));
+    parent.appendChild(new NavigationTreeNode('b'));
+    parent.appendChild(new NavigationTreeNode('c'));
+    var result = parent.map((child, index) => {
+      return child.getValue();
+    });
+
+    expect(result).toEqual(['a', 'b', 'c']);
+  });
+
+  it('should traverse some children', () => {
+    var parent = new NavigationTreeNode();
+    parent.appendChild(new NavigationTreeNode('a'));
+    parent.appendChild(new NavigationTreeNode('b'));
+    parent.appendChild(new NavigationTreeNode('c'));
+
+    var result = [];
+    var value = parent.some((child, index) => {
+      if (index > 1) {
+        return true;
+      } else {
+        result[index] = child.getValue();
+      }
+    });
+
+    expect(value).toEqual(true);
+    expect(result).toEqual(['a', 'b']);
+  });
+});