Merge pull request #120 from runtimejs/code-style

Update everything to ES6 and adopt a code style

Author: facekapow

.eslintignore

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+js/deps/
+js/modules/inherits.js

.eslintrc

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+extends:
+  - airbnb-base
+
+globals:
+  debug: true
+  __SYSCALL: true
+  runtime: true
+
+env:
+  es6: true
+  node: true
+
+rules:
+  strict:
+    - 2
+    - 'global'
+  max-len:
+    - 1
+    -
+      code: 100
+      tabWidth: 2
+      ignoreComments: true
+      ignoreUrls: true
+  consistent-return: 0
+  no-underscore-dangle: 0
+  global-require: 0
+  import/no-extraneous-dependencies: 0
+  no-return-assign: 1
+  new-cap: 1
+  no-console: 0
+  wrap-iife:
+    - 2
+    - 'inside'
+  no-use-before-define:
+    - 2
+    -
+      functions: false
+      classes: true
+  no-param-reassign:
+    - 2
+    -
+      props: false
+
+parserOptions:
+  ecmaVersion: 6
+  sourceType: 'script'
+  ecmaFeatures:
+    modules: false
+    defaultParams: true
+    classes: true
+    arrowFunctions: true
+    blockBindings: true
+    forOf: true
+    spread: true
+    templateStrings: true

CONTRIBUTING.md

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+# Contributing to runtime.js
+
+First off, thanks for deciding to contribute! :+1:
+
+## Got an issue?
+
+ * Make sure the issue isn't already reported by checking in [Issues](https://github.com/runtimejs/runtime/issues).
+ * Include the version of the kernel and JavaScript library in the issue description.
+ * Include a description of what happens and what the expected behavior is.
+
+## Cool feature request?
+
+ * Make sure the feature isn't already requested by checking in [Issues](https://github.com/runtimejs/runtime/issues).
+ * Include good reasons for why you think it should be added and why it'd be a good feature.
+ * If possible, include resources (links, examples, etc.) for anyone planning to add the feature.
+
+## Something to improve, add, or fix?
+
+### Kernel change (C++)
+
+Make sure that:
+ * the kernel is compilable by running `scons` (more information [here](https://github.com/runtimejs/runtime/wiki/Build)).
+ * the system can still boot up normally.
+ * the new/fixed/changed feature/bug works (of course, :smile:).
+
+### Library change (JavaScript)
+
+Make sure that:
+ * you run `npm run lint` at the root of repository (you'll also need to have installed dependencies beforehand with `npm install`) and get rid of any lint before commiting.
+ * the system can still boot up normally.
+ * the new/fixed/changed feature/bug works.
+ * the code is written in as much ES6 as possible and it conforms to the style guide found [here](https://github.com/airbnb/javascript) (with a [few exceptions](docs/code-style-exceptions.md)).

docs/code-style-exceptions.md

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+# Code Style Exceptions
+
+The JavaScript code adheres to the style guide found [here](https://github.com/airbnb/javascript), but with some exceptions:
+
+## No ES6 Modules
+
+V8 support for native ES6 modules is under development, so for now use `require` like you would in Node.
+All other ES6 features (classes, destructuring, default parameters, etc.) can be used freely.
+
+## Using `for-of` and `for-in`
+
+You're free to use `for-of` and `for-in` as necessary, however it's better to use `for (let value of object)` for values and `for (let key of Object.keys(object))` for keys.
+You can still use `for-in`, just be sure you know [the catch](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in#Iterating_over_own_properties_only) when using it.
+
+## Using 'dangling' underscores
+
+You *can* use 'dangling' underscores to denote a private member on an object or class.
+Some APIs were written before this style was adopted which use underscores for private members and probably won't be changed for compatibility.
+However, for any new APIs, it'd be preferred to use a [`Symbol`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol) instead, like:
+
+```js
+const somePrivateVarName = Symbol('somePrivateVarName');
+
+class Demo {
+  constructor() {
+    this[somePrivateVarName] = 'my value';
+  }
+  getMyPrivateVar() {
+    return this[somePrivateVarName];
+  }
+}
+```
+
+## Using `get` and `set`
+
+You can (and should) use ES6 `get` and `set` in new APIs, it's already used in various runtime.js APIs.
+
+## Assigning to functions parameters
+
+You cannot reassign *functions parameters*, but you can assign to *properties of* function parameters.
+```js
+// yes
+const demo = (myObject) => {
+  myObject.someProperty = 'my value';
+  // ...
+}
+
+// no
+const demo = (myObject) => {
+  myObject = {
+    someProperty: 'my value'
+  };
+  // ...
+}
+```
+
+## Wrapping an IIFE
+
+The invocation should be *outside* the parentheses, not inside.
+
+```js
+// yes
+(function() {
+  // ...
+})();
+
+// no
+(function() {
+
+}());
+```