Today I found a question on github about how to correctly use javascript for our program development. I shamelessly came up with an original... It's a scam. Let's share it with you.
A mostly reasonable approach to Javascript.
Types // Type
Objects //Objects
Arrays //Arrays
Strings //Strings
Functions //Functions
Properties //Properties
Variables //Variables
Hoisting //Variable improvement
Conditional Expressions & Equality // Conditional expressions and equations.
Blocks //Block Code
Comments //Comments
Whitespace //Space
Commas //Commas
Semicolons //Semicolons
Type Casting & Coercion //Type Conversion
Naming Conventions //Naming Rules
Accessors //Access
Constructors //Constructors
Events //Time
Modules //Models
jQuery //
ECMAScript 5 Compatibility //ECMA 5 Compatibility
Testing //Testing
Performance //Performance
Resources //Resources
In the Wild
Translation
The JavaScript Style Guide Guide
Contributors
License
Types (type)
Primitive type: When accessing a primitive type, it actually directly accesses the contents of the primitive type.
string
number
boolean
null
undefined
var foo = 1,
bar = foo;
bar = 9;
(foo,bar); //=> 1,9
Complex type: When you access a complex type data type, you actually access the value of the variable through a reference.
object
array
function
var foo = [1,2]; bar = foo; bar[0] = 9; (foo[0],bar[0]); // => 9,9
object(object)
Use object literal to create an object (literal)
//bad
var item = new Object();
//good
var item = {};
Do not use reserved keywords as the object's property name. 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 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 for insertion operation
var someStack = [];
//bad
someStack[] = 'vein';
//good
('vein');
When you want to copy an array, use
var len = , //Refers to the above content...itemCopy = [],
i;
//bad
for(i = 0; i < len ; ++i){
itemCopy[i] = items[i];
}
//good
itemCopy = (); //Pay attention here.I really don't know this...
Strings string
Use single quotes to enclose strings...//I haven't found a suitable explanation for performance here, I personally like to use it like this, (it's better to wear less than wear...you know...)
//bad var name = "Bob Parr"; //good var name = 'Bob Parr'; //bad var fullName = "Bob " + ; //good var fullName = 'Bob ' + ;
When strings are longer than 80 characters, you need to use string concatenation to write on multiple lines. Note that if overuse, concatenation of 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 you have a plan, create an array, like the following. The effect will be better if you use it...
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 = ;
//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>' + ('</li><li>') + '</li></ul>';
}
Functions
//Anonymous function expression..var anonymous = function(){
return true;
};
// Named function expressions.var named = function named(){
return true;
};
//Instant reference function(function(){
('Welcome to the Internet. Please follow me.');
})();
Never define functions in non-function block code (if, while). Correspondingly, the function is assigned to the external variable name in the middle of the code block.
//bad
if(currentUser){
function test(){
('Nope.');
}
}
//good
var test;
if(currentUser){
test = function(){
('Yup');
}; //be careful with the semi-colon.
}
Properties (Properties)
Use dot syntax to access properties.
var luke = {
jedi: true,
age: 28
};
//bad
var isJedi = luke['jedi'];
//good
var isJedi = ;
When accessing object properties using variables, use [] square brackets to access
var luke = {
jedi: true,
age: 28
};
function getProp(prop) {
return luke[prop];
}
var isJedi = getProp('jedi');