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

Author: Joris-van-der-Wel

lib/SymbolTree.js

@@ -252,21 +252,18 @@ class SymbolTree {
          * @method childrenToArray
          * @memberOf module:symbol-tree#
          * @param {Object} parent
-         * @param {Object[]} [array=[]]
-         * @param {Function} [filter] Function to test each object before it is added to the array.
+         * @param {Object} [options]
+         * @param {Object[]} [options.array=[]]
+         * @param {Function} [options.filter] Function to test each object before it is added to the array.
          *                            Invoked with arguments (object). Should return `true` if an object
          *                            is to be included.
-         * @param {*} [thisArg] Value to use as `this` when executing `filter`.
+         * @param {*} [options.thisArg] Value to use as `this` when executing `filter`.
          * @return {Object[]}
          */
-        childrenToArray(parent, array, filter, thisArg) {
-                if (!array) {
-                        array = [];
-                }
-
-                if (!filter) {
-                        filter = returnTrue;
-                }
+        childrenToArray(parent, options) {
+                const array   = (options && options.array  ) || [];
+                const filter  = (options && options.filter ) || returnTrue;
+                const thisArg = (options && options.thisArg) || undefined;
 
                 let object = this._node(parent).first;
                 let index = 0;

test/SymbolTree.js

@@ -632,7 +632,7 @@ test('childrenToArray', function(t) {
         t.deepEqual([aa, ab, ac], tree.childrenToArray(a));
 
         const arr = ['a', 5];
-        tree.childrenToArray(a, arr);
+        tree.childrenToArray(a, {array: arr});
         t.deepEqual(['a', 5, aa, ab, ac], arr);
 
         t.end();
@@ -659,7 +659,7 @@ test('childrenToArray with filter', function(t) {
                 return object !== ab;
         };
 
-        t.deepEqual([aa, ac], tree.childrenToArray(a, null, filter));
+        t.deepEqual([aa, ac], tree.childrenToArray(a, {filter: filter}));
 
         const thisArg = {a: 123};
         const filterThis = function(object) {
@@ -668,7 +668,7 @@ test('childrenToArray with filter', function(t) {
                 return object !== ab;
         };
 
-        t.deepEqual([aa, ac], tree.childrenToArray(a, null, filterThis, thisArg));
+        t.deepEqual([aa, ac], tree.childrenToArray(a, {filter: filterThis, thisArg: thisArg}));
 
         t.end();
 });