How to use javascript correctly for our program development_javascript skills

Today I found an article on github about how to use javascript correctly to develop our programs. I shamelessly came up with an original one...it's a scam. Let's share it with everyone.
A mostly reasonable approach to Javascript.
Types //Type
Objects //Object
Arrays //Array
Strings //String
Functions //Function
Properties //Properties
Variables //Variables
Hoisting //Variable hoisting
Conditional Expressions & Equality //Conditional expressions and equations.
Blocks //Block code
Comments //Comments
Whitespace //space
Commas //comma
Semicolons //Semicolon
Type Casting & Coercion //Type conversion
Naming Conventions //Naming rules
Accessors //Access
Constructors //Constructor
Events //Time
Modules //Model
jQuery //
ECMAScript 5 Compatibility //ECMA 5 compatible
Testing //Testing
Performance //Performance
Resources //Resources
In the Wild
Translation
The JavaScript Style Guide Guide
Contributors
License

Types
Primitive type: When accessing a primitive type, the content of the primitive type is actually accessed directly.
string
number
boolean
null
undefined
var foo = 1,
bar = foo;
bar = 9;
console.log(foo,bar); //=> 1,9

Complex type: When you access a complex type data type, you actually access the value of the variable by reference.
object
array
function

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

object(object)
Use object literals to create objects (literal)

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

Do not use reserved keywords as object property names. This will not work under IE8.

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

array(array)
Also use literal methods to create arrays

//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 perform the insertion operation

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

When you want to copy an array, use array.slice

var len = items.length, //指的就是上面的内容...
itemCopy = [],
i;
//bad
for(i = 0; i < len ; ++i){
itemCopy[i] = items[i];
}
//good
itemCopy = items.slice(); //这里要注意了.这个我还真不知道...

Strings string
Use single quotes to surround the string...//I didn't find a suitable explanation about performance here. I personally like to use it this way, (wearing less is better than wearing more, right? ..you know..)

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

When the string is longer than 80 characters, you need to use string concatenation to write on multiple lines. Note that if used excessively, concatenating strings will affect performance

// 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 it is planned to create an array, as shown below. Using Array.join will have better results..

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

//匿名函数表达式..
var anonymous = function(){
return true;
};
// 命名函数表达式.
var named = function named(){
return true;
};
//即时引用函数
(function(){
console.log('Welcome to the Internet. Please follow me.');
})();

Never define functions in non-function block code (if, while). Correspondingly, assign functions to external variable names in the middle of the code block..

//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 dot syntax to access properties.

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

When using variables to access object properties, use [] square brackets to access

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