Npm updates

.babelrc.json

@@ -0,0 +1,3 @@
+{
+    "presets": ["@babel/preset-env"]
+}

.editorconfig

@@ -0,0 +1,18 @@
+# This file is for unifying the coding style for different editors and IDEs
+# editorconfig.org
+
+root = true
+
+[*]
+end_of_line = lf
+charset = utf-8
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 4
+
+[*.json]
+indent_size = 2
+
+[*.yml]
+indent_size = 2

.eslintignore

@@ -0,0 +1,5 @@
+node_modules
+dist
+
+!.eslintrc.js
+coverage

.eslintrc.js

@@ -0,0 +1,48 @@
+'use strict';
+module.exports = {
+    env: {
+        browser: true,
+        commonjs: true,
+        es6: true,
+        node: true
+    },
+    extends: 'eslint:recommended',
+    globals: {
+        Atomics: 'readonly',
+        SharedArrayBuffer: 'readonly'
+    },
+    overrides: [{
+        files: '.eslintrc.js',
+        parserOptions: {
+            sourceType: 'script'
+        },
+        rules: {
+            strict: 'error'
+        }
+    }, {
+        files: 'test/**',
+        globals: {
+            expect: true
+        },
+        env: {
+            mocha: true
+        }
+    }],
+    parserOptions: {
+        sourceType: 'module',
+        ecmaVersion: 2018
+    },
+    rules: {
+        semi: ['error'],
+        indent: ['error', 4, { SwitchCase: 1 }],
+        'prefer-const': ['error'],
+        'no-var': ['error'],
+        'prefer-destructuring': ['error'],
+        'object-shorthand': ['error'],
+        'object-curly-spacing': ['error', 'always'],
+        quotes: ['error', 'single'],
+        'quote-props': ['error', 'as-needed'],
+        'brace-style': ['error', '1tbs', { allowSingleLine: true }],
+        'prefer-template': ['error']
+    }
+};

.npmrc

@@ -0,0 +1 @@
+package-lock = false

.travis.yml

@@ -1,6 +1,6 @@
 sudo: false
 language: node_js
 node_js:
-  - "6"
-  - "8"
-  - "10"
+  - 10
+  - 12
+  - 14

LICENSE.BSD

@@ -0,0 +1,19 @@
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+  * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+  * Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

README.md

@@ -10,7 +10,7 @@ The following code will output all variables declared at the root of a file.
 
 ```javascript
 esrecurse.visit(ast, {
-    XXXStatement: function (node) {
+    XXXStatement (node) {
         this.visit(node.left);
         // do something...
         this.visit(node.right);
@@ -21,8 +21,8 @@ esrecurse.visit(ast, {
 We can use `Visitor` instance.
 
 ```javascript
-var visitor = new esrecurse.Visitor({
-    XXXStatement: function (node) {
+const visitor = new esrecurse.Visitor({
+    XXXStatement (node) {
         this.visit(node.left);
         // do something...
         this.visit(node.right);
@@ -36,8 +36,7 @@ We can inherit `Visitor` instance easily.
 
 ```javascript
 class Derived extends esrecurse.Visitor {
-    constructor()
-    {
+    constructor() {
         super(null);
     }
 
@@ -76,7 +75,7 @@ We can use user-defined node types.
 
 ```javascript
 // This tree contains a user-defined `TestExpression` node.
-var tree = {
+const tree = {
     type: 'TestExpression',
 
     // This 'argument' is the property containing the other **node**.
@@ -91,7 +90,7 @@ var tree = {
 esrecurse.visit(
     ast,
     {
-        Literal: function (node) {
+        Literal (node) {
             // do something...
         }
     },
@@ -113,7 +112,7 @@ Please note circular references cause the stack overflow. AST might have circula
 esrecurse.visit(
     ast,
     {
-        Literal: function (node) {
+        Literal (node) {
             // do something...
         }
     },
@@ -130,13 +129,13 @@ Please note circular references cause the stack overflow. AST might have circula
 esrecurse.visit(
     ast,
     {
-        Literal: function (node) {
+        Literal (node) {
             // do something...
         }
     },
     {
-        fallback: function (node) {
-            return Object.keys(node).filter(function(key) {
+        fallback (node) {
+            return Object.keys(node).filter((key) => {
                 return key !== 'argument'
             });
         }

esrecurse.js

@@ -1,3 +1,5 @@
+// Todo: Remove eslint disable directive once have a Babel routine
+/* eslint-disable no-var, prefer-template */
 /*
   Copyright (C) 2014 Yusuke Suzuki <[email protected]>
 
@@ -27,6 +29,7 @@
     var estraverse = require('estraverse');
 
     function isNode(node) {
+        // istanbul ignore if -- Is currently always truthy
         if (node == null) {
             return false;
         }