Merge pull request airbnb#220 from justjake/master

Switch to one-variable-per-var from many-variables-per-var

Author: hshoff

README.md

@@ -50,8 +50,8 @@
  + `undefined`
 
  ```javascript
- var foo = 1,
-   bar = foo;
+ var foo = 1;
+ var bar = foo;
 
  bar = 9;
 
@@ -64,8 +64,8 @@
  + `function`
 
  ```javascript
- var foo = [1, 2],
-   bar = foo;
+ var foo = [1, 2];
+ var bar = foo;
 
  bar[0] = 9;
 
@@ -151,9 +151,9 @@
  - When you need to copy an array use Array#slice. [jsPerf](http://jsperf.com/converting-arguments-to-an-array/7)
 
  ```javascript
- var len = items.length,
-  itemsCopy = [],
-   i;
+ var len = items.length;
+ var itemsCopy = [];
+ var i;
 
  // bad
  for (i = 0; i < len; i++) {
@@ -216,10 +216,10 @@
  - When programmatically building up a string, use Array#join instead of string concatenation. Mostly for IE: [jsPerf](http://jsperf.com/string-vs-array-concat/2).
 
  ```javascript
- var items,
-  messages,
-  length,
-   i;
+ var items;
+ var messages;
+ var length;
+ var i;
 
  messages = [{
  state: 'success',
@@ -366,18 +366,27 @@
  var superPower = new SuperPower();
  ```
 
- - Use one `var` declaration for multiple variables and declare each variable on a newline.
+ - Use one `var` declaration per variable.
+ It's easier to add new variable declarations this way, and you never have
+ to worry about swapping out a `;` for a `,` or introducing punctuation-only
+ diffs. 
 
  ```javascript
  // bad
- var items = getItems();
- var goSportsTeam = true;
- var dragonball = 'z';
-
- // good
  var items = getItems(),
  goSportsTeam = true,
  dragonball = 'z';
+
+ // bad
+ // (compare to above, and try to spot the mistake)
+ var items = getItems(),
+ goSportsTeam = true;
+ dragonball = 'z';
+
+ // good
+ var items = getItems();
+ var goSportsTeam = true;
+ var dragonball = 'z';
  ```
 
  - Declare unassigned variables last. This is helpful when later on you might need to assign a variable depending on one of the previous assigned variables.
@@ -389,17 +398,18 @@
  goSportsTeam = true;
 
  // bad
- var i, items = getItems(),
- dragonball,
- goSportsTeam = true,
- len;
+ var i;
+ var items = getItems();
+ var dragonball;
+ var goSportsTeam = true;
+ var len;
 
  // good
- var items = getItems(),
-  goSportsTeam = true,
-  dragonball,
-  length,
-   i;
+ var items = getItems();
+ var goSportsTeam = true;
+ var dragonball;
+ var length;
+ var i;
  ```
 
  - Assign variables at the top of their scope. This helps avoid issues with variable declaration and assignment hoisting related issues.
@@ -639,8 +649,8 @@
  // make() returns a new element
  // based on the passed in tag name
  //
- // @param <String> tag
- // @return <Element> element
+ // @param {String} tag
+ // @return {Element} element
  function make(tag) {
 
  // ...stuff...
@@ -653,8 +663,8 @@
  * make() returns a new element
  * based on the passed in tag name
  *
- * @param <String> tag
- * @return <Element> element
+ * @param {String} tag
+ * @return {Element} element
  */
  function make(tag) {
 
@@ -843,14 +853,18 @@
 
  ```javascript
  // bad
- var once
+ var story = [
+ once
  , upon
- , aTime;
+ , aTime
+ ];
 
  // good
- var once,
- upon,
- aTime;
+ var story = [
+ once,
+ upon,
+ aTime
+ ];
 
  // bad
  var hero = {