Nodes with children

node.js

function Node ( val, parent ) {
  this.value = val;
  this.setParent( parent );
  this.children = [];
}

Node.prototype = {
  addChild: function ( val ) {
    var node = val instanceof Node ? val : new Node( val );
    node.setParent( this );
    this.children.push( node );
  },
  setParent: function ( node ) {
    this.parent = node;
  } 
};

var a = new Node( "a" );
a.addChild("x");
a.addChild("y");
a.addChild("z");

// the node
console.log( a );

var kids = a.children;

// check parent
console.log( kids[0].parent === a ); // true