Use an options argument instead of various arguments, for following()

Author: Joris-van-der-Wel

lib/SymbolTree.js

@@ -207,13 +207,17 @@ class SymbolTree {
          * @method following
          * @memberOf module:symbol-tree#
          * @param {!Object} object
-         * @param {Object} [treeRoot] If set, `treeRoot` must be an inclusive ancestor
+         * @param {Object} [options]
+         * @param {Object} [options.root] If set, `root` must be an inclusive ancestor
          *        of the return value (or else null is returned). This check _assumes_
          *        that `root` is also an inclusive ancestor of the given `node`
-         * @param {Boolean} [skipChildren=false] If set, ignore the childen of `object`
+         * @param {Boolean} [options.skipChildren=false] If set, ignore the children of `object`
          * @returns {?Object}
          */
-        following(object, treeRoot, skipChildren) {
+        following(object, options) {
+                const treeRoot = options && options.root;
+                const skipChildren = options && options.skipChildren;
+
                 const first = !skipChildren && this._node(object).first;
 
                 if (first) {
@@ -348,7 +352,7 @@ class SymbolTree {
                         if (filter.call(thisArg, object)) {
                                 array.push(object);
                         }
-                        object = this.following(object, root);
+                        object = this.following(object, {root: root});
                 }
 
                 return array;

lib/TreeIterator.js

@@ -40,7 +40,7 @@ class TreeIterator {
                         this[NEXT] = tree.preceding(value, {root: root});
                 }
                 else /*if (iterateFunc === 5)*/ {
-                        this[NEXT] = tree.following(value, root);
+                        this[NEXT] = tree.following(value, {root: root});
                 }
 
                 return {

test/SymbolTree.js

@@ -591,11 +591,11 @@ test('following using a specified root', function(t) {
         tree.insertLast(aaa, aa);
         tree.insertAfter(b, a);
 
-        t.equal(null, tree.following(aaa, aaa));
-        t.equal(null, tree.following(aaa, aa));
-        t.equal(null, tree.following(aaa, a));
-        t.equal(aa  , tree.following(a, a));
-        t.equal(aaa , tree.following(aa, a));
+        t.equal(null, tree.following(aaa, {root: aaa}));
+        t.equal(null, tree.following(aaa, {root: aa}));
+        t.equal(null, tree.following(aaa, {root: a}));
+        t.equal(aa  , tree.following(a  , {root: a}));
+        t.equal(aaa , tree.following(aa , {root: a}));
 
         t.end();
 });
@@ -609,7 +609,7 @@ test('following with skipChildren', function(t) {
         tree.insertLast(aa, a);
         tree.insertAfter(b, a);
 
-        t.equal(b, tree.following(a, null, true));
+        t.equal(b, tree.following(a, {skipChildren: true}));
 
         t.end();
 });