Use ESLint to ensure uniform and modern JavaScript syntax

js-jose's code has allowed for mixing snake camel case, varying
indentation practices etc. I'm sure this could have been addressed with
proper jshint config, but having used ESLint in the past, it seems to
make a better job at enforcing rules and also auto-fixing small mishaps.

I've picked standardjs.com as the basis for the JavaScript style, with
one omission -- unlike standardjs, js-jose will still use semicolons
everywhere (happy to change it, but seemed like a bigger change that
could happen in a separate PR).

.eslintrc.json

@@ -0,0 +1,21 @@
+{
+    "env": {
+        "browser": true,
+        "es6": true,
+        "node": true
+    },
+    "extends": [
+        "standard"
+    ],
+    "globals": {
+        "Atomics": "readonly",
+        "SharedArrayBuffer": "readonly"
+    },
+    "parserOptions": {
+        "ecmaVersion": 2018,
+        "sourceType": "module"
+    },
+    "rules": {
+      "semi": ["error", "always"]
+    }
+}

CONTRIBUTING.md

@@ -5,7 +5,7 @@ forking the repository and sending a pull request.
 
 When submitting code, please make every effort to follow existing conventions
 and style in order to keep the code as readable as possible. Please also make
-sure all tests pass by running `make test`.
+sure all tests pass by running `npm run build`.
 
 Before your code can be accepted into the project you must also sign the
 Individual Contributor License Agreement.  We use [cla-assistant.io][1] and you

Gruntfile.js

@@ -6,11 +6,11 @@ module.exports = function(grunt) {
   var config = {
     pkg: grunt.file.readJSON('package.json'),
 
-    jshint: {
-      all: ['Gruntfile.js', 'lib/*.js'],
+    eslint: {
       options: {
-        "esversion": 6
-      }
+        fix: true
+      },
+      target: 'lib'
     },
 
     webpack: {
@@ -26,13 +26,13 @@ module.exports = function(grunt) {
           },
           reporters: ['coverage', 'progress'],
           coverageReporter: {
-            type : 'lcovonly',
-            dir : 'coverage/'
+            type: 'lcovonly',
+            dir: 'coverage/'
           },
           frameworks: ['qunit'],
           files: [
-            {pattern: 'dist/jose.js', watching: false, included: false},
-            {pattern: 'test/qunit-promises.js', watching: false, included: false},
+            { pattern: 'dist/jose.js', watching: false, included: false },
+            { pattern: 'test/qunit-promises.js', watching: false, included: false },
             'test/jose-jwe-test.html',
             'test/jose-jws-ecdsa-test.html',
             'test/jose-jws-rsa-test.html'
@@ -46,15 +46,15 @@ module.exports = function(grunt) {
             }
           },
           singleRun: true,
-          plugins:['karma-coverage', 'karma-qunit', 'karma-chrome-launcher']
+          plugins: ['karma-coverage', 'karma-qunit', 'karma-chrome-launcher']
         }
       },
       without_coverage: {
         options: {
           frameworks: ['qunit'],
           files: [
-            {pattern: 'dist/jose.js', watching: false, included: false},
-            {pattern: 'test/qunit-promises.js', watching: false, included: false},
+            { pattern: 'dist/jose.js', watching: false, included: false },
+            { pattern: 'test/qunit-promises.js', watching: false, included: false },
             'test/jose-jwe-test.html',
             'test/jose-jws-ecdsa-test.html',
             'test/jose-jws-rsa-test.html'
@@ -90,12 +90,12 @@ module.exports = function(grunt) {
   grunt.initConfig(config);
 
   grunt.loadNpmTasks('grunt-contrib-concat');
-  grunt.loadNpmTasks('grunt-contrib-jshint');
+  grunt.loadNpmTasks('grunt-eslint');
   grunt.loadNpmTasks('grunt-contrib-uglify');
   grunt.loadNpmTasks('grunt-karma');
   grunt.loadNpmTasks('grunt-karma-coveralls');
   grunt.loadNpmTasks('grunt-webpack');
 
-  grunt.registerTask('default', ['jshint', 'webpack', 'karma:without_coverage']);
-  grunt.registerTask('with_coverage', ['jshint', 'webpack', 'karma:with_coverage']);
+  grunt.registerTask('default', ['eslint', 'webpack', 'karma:without_coverage']);
+  grunt.registerTask('with_coverage', ['eslint', 'webpack', 'karma:with_coverage']);
 };

README.md

@@ -4,6 +4,8 @@ Javascript library for Jose JWE and JWS
 [![license](http://img.shields.io/badge/license-apache_2.0-red.svg?style=flat)](https://raw.githubusercontent.com/square/js-jose/master/LICENSE)
 [![build](https://travis-ci.org/square/js-jose.svg?branch=master)](https://travis-ci.org/square/js-jose)
 [![coverage](https://img.shields.io/coveralls/square/js-jose.svg?branch=master&style=flat)](https://coveralls.io/r/square/js-jose)
+[![JavaScript Style Guide](https://img.shields.io/badge/code_style-standard-brightgreen.svg)](https://standardjs.com)
+
 
 Overview
 --------