How to use javascript correctly to develop our program

Today on github we found an article on how to use javascript correctly for our application development. Pit dad. Bring to share with everybody.
A mostly reasonable approach to Javascript.
Types / / type
Objects / / object
The Arrays / / array
Strings // Strings
Functions provides / / function
The Properties / / Properties
The Variables / / Variables
Hoisting / / variable to ascend
Conditional Expressions & Equality // Conditional Expressions and equations.
Blocks // block code
Comments / / comment
Whitespace / / space
Commas / / comma
Semicolons / / a semicolon
Type Casting & Coercion / / Type conversion
Naming Conventions // Naming rules
Accessors, / / access
Constructors // Constructors
The Events / / time
Modules / / model
JQuery / /
ECMAScript 5 Compatibility //ECMA 5 Compatibility
Testing / / test
The Performance / / Performance
Resources / / Resources
In the Wild
Translation
The JavaScript Style Guide Guide
Contributors
License

Types (Types)
Primitive type: when accessing a primitive type, you actually access the contents of that primitive type directly.
The string
number
Boolean
null
undefined
Var foo = 1,
The bar = foo;
The bar = 9;
The console. The log (foo, bar); / / = > 1, 9

Complex types: when you access a complex type data type, you are accessing the value of the variable by reference.
The object
array
The function

var foo = [1,2];
bar = foo;
bar[0] = 9;
console.log(foo[0],bar[0]); // => 9,9

The object (objects)
Using object literals to create objects

//bad
var item = new Object();
//good
var item = {};

Do not use reserved keywords as property names for objects. This does not work under IE8.

//bad
var superman = {
default: {clark: 'kent'},
private: true
};
//good
var superman = {
defaults: {clark: 'kent'},
hidden: true
};

Array (array)
Also use the literal method to create an array

//bad
var items = new Array();
//good
var items = [];

If you don't know the length of the Array, use Array's built-in method, push, to insert it

var someStack = [];
//bad
someStack[someStack.length] = 'vein';
//good
someStack.push('vein');

Use array.slice when you want to copy an array

var len = items.length, //That's what it says...
itemCopy = [],
i;
//bad
for(i = 0; i < len ; ++i){
itemCopy[i] = items[i];
}
//good
itemCopy = items.slice(); // Here's the thing to watch out for . I didn't know that ...

Strings Strings
Use single quotes to surround strings... // I can't find a proper performance explanation here, and I like to use it myself. You know..)

//bad
var name = "Bob Parr";
//good
var name = 'Bob Parr';
//bad
var fullName = "Bob " + this.lastName;
//good
var fullName = 'Bob ' + this.lastName;

Strings longer than 80 characters need to be written on multiple lines using string concatenation.. Note that the connection string can affect performance if overused

// bad
var errorMessage = 'This is a super long error that was thrown because of Batman. When you stop to think about how Batman had anything to do with this, you would get nowhere fast.';
// bad
var errorMessage = 'This is a super long error that was thrown because 
of Batman. When you stop to think about how Batman had anything to do 
with this, you would get nowhere 
fast.';
// good
var errorMessage = 'This is a super long error that was thrown because ' +
'of Batman. When you stop to think about how Batman had anything to do ' +
'with this, you would get nowhere fast.';

If you are creating an Array by design, use array.join as follows.

var items,
messages,
length,
i;
messages = [{
stat: 'success',
message: ' This one worked'
},{
stat: 'success',
message: ' This one worked'
},{
stat: 'success',
message: ' This one worked'
}
];
length = messages.length;
//bad
function inbox(messages){
items = '<ul>';
for (i = 0; i < length; i++) {
items += '<li>' + messages[i].message + '</li>';
}
return items + '</ul>';
}
//good
function inbox(messages){
items = [];
for( i = 0; i < length ; i++){
items[i] = messages[i].message;
}
return '<ul><li>' + items.join('</li><li>') + '</li></ul>';
}

Functions (Functions provides)

//Anonymous function expression..
var anonymous = function(){
return true;
};
//Name the function expression.
var named = function named(){
return true;
};
//Immediate reference function
(function(){
console.log('Welcome to the Internet. Please follow me.');
})();

Never define a function in a non-functional block code (if,while).

//bad
if(currentUser){
function test(){
console.log('Nope.');
}
}
//good
var test;
if(currentUser){
test = function(){
console.log('Yup'); 
}; //be careful with the semi-colon.
}

Properties
Use the dot syntax to access properties.

var luke = {
jedi: true,
age: 28
};
//bad
var isJedi = luke['jedi'];
//good
var isJedi = luck.jedi;

When using a variable to access an object property, use [] square brackets to access it

var luke = {
jedi: true,
age: 28
};
function getProp(prop) {
return luke[prop];
}
var isJedi = getProp('jedi');