Merge remote-tracking branch 'gh/master'

Author: taoqf

.eslintrc

@@ -1,32 +1,14 @@
-root: true
-
-env:
-  node: true
-  mocha: true
-
-extends:
-  "eslint:recommended"
-
-rules:
-  array-bracket-spacing: [2, "never"]
-  block-scoped-var: 2
-  brace-style: [2, "1tbs"]
-  camelcase: 1
-  curly: 2
-  eol-last: 2
-  eqeqeq: [2, "smart"]
-  indent: [2, 2, { "SwitchCase": 1 }]
-  max-depth: [1, 3]
-  max-len: [1, 80]
-  max-statements: [1, 15]
-  new-cap: 1
-  no-extend-native: 2
-  no-mixed-spaces-and-tabs: 2
-  no-trailing-spaces: 2
-  no-unused-vars: 1
-  no-use-before-define: [2, "nofunc"]
-  object-curly-spacing: [2, "never"]
-  quotes: [2, "single", "avoid-escape"]
-  semi: [2, "always"]
-  space-after-keywords: [2, "always"]
-  space-unary-ops: 2
+{
+  "extends": "eslint:recommended",
+  "rules": {
+    "comma-dangle": "off"
+  },
+  "env": {
+    "browser": true,
+    "node": true,
+    "mocha": true
+  },
+  "parserOptions": {
+    "ecmaVersion": 6
+  }
+}

.prettierrc

@@ -0,0 +1,4 @@
+{
+  "singleQuote": true,
+  "trailingComma": "none"
+}

.travis.yml

@@ -7,6 +7,7 @@ notifications:
   email: false
 node_js:
   - 'stable'
+  - '6'
 branches:
   except:
     - "/^v\\d+\\.\\d+\\.\\d+$/"

index.js

@@ -1,24 +1,25 @@
 'use strict';
-var property = require('nested-property');
-var keyBy = require('lodash.keyby');
+const property = require('nested-property');
+const keyBy = require('lodash.keyby');
 
-var isArray = Array.isArray || function (arg) {
-	return Object.prototype.toString.call(arg) === '[object Array]';
-};
-
-var createTree = function (array, rootNodes, customID, childrenProperty) {
-	var tree = [];
+const createTree = (array, rootNodes, customID, childrenProperty) => {
+	const tree = [];
 
-	for (var rootNode in rootNodes) {
-		var node = rootNodes[rootNode];
-		var childNode = array[node[customID]];
+	for (const rootNode in rootNodes) {
+		const node = rootNodes[rootNode];
+		const childNode = array[node[customID]];
 
 		if (!node && !rootNodes.hasOwnProperty(rootNode)) {
 			continue;
 		}
 
 		if (childNode) {
-			node[childrenProperty] = createTree(array, childNode, customID, childrenProperty);
+			node[childrenProperty] = createTree(
+				array,
+				childNode,
+				customID,
+				childrenProperty
+			);
 		}
 
 		tree.push(node);
@@ -27,11 +28,11 @@ var createTree = function (array, rootNodes, customID, childrenProperty) {
 	return tree;
 };
 
-var groupByParents = function (array, options) {
-	var arrayByID = keyBy(array, options.customID);
+const groupByParents = (array, options) => {
+	const arrayByID = keyBy(array, options.customID);
 
-	return array.reduce(function (prev, item) {
-		var parentID = property.get(item, options.parentProperty);
+	return array.reduce((prev, item) => {
+		let parentID = property.get(item, options.parentProperty);
 		if (!parentID || !arrayByID.hasOwnProperty(parentID)) {
 			parentID = options.rootID;
 		}
@@ -58,24 +59,34 @@ var groupByParents = function (array, options) {
  * @param {Object} options An object containing the following fields:
  *
  *  - `parentProperty` (String): A name of a property where a link to
- *     a parent node could be found. Default: 'parent_id'
+ * a parent node could be found. Default: 'parent_id'
  *  - `customID` (String): An unique node identifier. Default: 'id'
+ *  - `childrenProperty` (String): A name of a property where children nodes
+ * are going to be stored. Default: 'children'.
  *
  * @return {Array} Result of transformation
  */
 
 module.exports = function arrayToTree(data, options) {
-	options = Object.assign({
-		childrenProperty: 'children',
-		parentProperty: 'parent_id',
-		customID: 'id',
-		rootID: '0'
-	}, options);
+	options = Object.assign(
+		{
+			parentProperty: 'parent_id',
+			childrenProperty: 'children',
+			customID: 'id',
+			rootID: '0'
+		},
+		options
+	);
 
-	if (!isArray(data)) {
+	if (!Array.isArray(data)) {
 		throw new TypeError('Expected an object but got an invalid argument');
 	}
 
-	var grouped = JSON.parse(JSON.stringify(groupByParents(data, options)));	// clone
-	return createTree(grouped, grouped[options.rootID], options.customID, options.childrenProperty);
+	const grouped = groupByParents(data.slice(), options);
+	return createTree(
+		grouped,
+		grouped[options.rootID],
+		options.customID,
+		options.childrenProperty
+	);
 };