Current Popular JavaScript Code Style Guide_Javascript Tips

JavaScript does not have an authoritative coding style guide. Instead, there are some popular coding styles:

Copy code The code is as follows:

Google’s JavaScript Style Guide (hereinafter referred to as Google)
http://google-styleguide.googlecode.com/svn/trunk/javascriptguide.xml
NPM coding style (hereinafter referred to as NPM)
https://npmjs.org/doc/coding-style.html
Felix’s Node.js Style Guide (hereinafter referred to as Node.js)
http://nodeguide.com/style.html
Idiomatic JavaScript (hereinafter referred to as Idiomatic)
https://github.com/rwldrn/idiomatic.js/
jQuery JavaScript Style Guide (hereinafter referred to as jQuery)
http://contribute.jquery.org/style-guide/js/
JavaScript Style Guide by Douglas Crockford (hereinafter referred to as Crockford), Douglas Crockford is one of the most well-known technical authorities in the field of web development and a member of the ECMA JavaScript 2.0 Standardization Committee
http://javascript.crockford.com/code.html

Of course, there are also some default setting choices in the JavaScript syntax checkers JSLint and JSHint. The question is, what is the ultimate JavaScript coding style that most developers can follow? Let’s find some consensus styles from these 6 style guides.

1. Code style comparison

1.1 Indentation

Two spaces, no longer indentation, no tab indentation: Google, NPM, Node.js, Idiomatic
Tab indent: jQuery
4 spaces: Crockford

1.2 Space between parameters and expressions

Use compact styles: Google, NPM, Node.js

Copy code The code is as follows:

project.MyClass = function(arg1, arg2) {

Excessive use of spaces: Idiomatic, jQuery

Copy code The code is as follows:

for ( i = 0; i < length; i ) {

No comments yet: Crockford
In most guidelines, developers are reminded not to have any spaces at the end of statements.

1.3 Code line length

Up to 80 characters: Google, NPM, Node.js, Crockford (When inside a code block, indentation other than 2 spaces allows aligning function arguments to the position of the first function argument. Another option Use 4 spaces for indentation when wrapping automatically)
No comments left: jQuery, Idiomatic

1.4 semicolon

Always use semicolons, don’t rely on implicit insertion: Google, Node.js, Crockford
Don't use expect in certain situations: NPM
No comments left: jQuery, Idiomatic

1.5 Notes

Follow JSDoc conventions: Google, Idiomatic
No comments left: NPM, Node.js, jQuery, Crockford

1.6 Quotes

Recommended single quotes: Google, Node.js
Double quotes: jQuery
No comments: NPM, Idiomatic, Crockford

1.7 Variable declaration

Declare one at a time, without commas: Node.js

Copy code The code is as follows:

var foo = ”;
var bar = ”;

Declare multiple at once, separated by commas at the end of the line: Idiomatic, jQuery

Copy code The code is as follows:

var foo = “”,
bar = “”,
quux;

Use comma at start of line: NPM
No comments: Google, Crockford

1.8 Braces

Use opening braces on the same line: Google, NPM, Node.js, Idiomatic, jQuery, Crockford

Copy code The code is as follows:

function thisIsBlock(){

The NPM guidelines state that curly braces should only be used if the block of code needs to contain the next line, otherwise not.

1.9 Global variables

Don’t use global variables: Google, Crockford (Google said that global variable naming conflicts are difficult to debug and may cause some troublesome problems when the two projects are being integrated. In order to facilitate the sharing of common JavaScript code, a convention needs to be established to Avoid conflicts. Crockford believes that implicit global variables should not be used)

No comments: Idiomatic, jQuery, NPM, Node.js

2 Naming style

2.1 Variable naming

The first word at the beginning is lowercase, and the first letter of all subsequent words is capitalized: Google, NPM, Node.js, Idiomatic

Copy code The code is as follows:

var foo = “”;
var fooName = “”;

2.2 Constant Naming

Use capital letters: Google, NPM, Node.js

Copy code The code is as follows:

var CONS = ‘VALUE’;

No comments left: jQuery, Idiomatic, Crockford

2.3 Function Naming

The first word at the beginning is lowercase, and the first letter of all subsequent words is capitalized (camel case): Google, NPM, Idiomatic, Node.js (it is recommended to use long, descriptive function names)

Copy code The code is as follows:

function veryLongOperationName
function short()..

Function naming in keyword form:

Copy code The code is as follows:

function isReady()
function setName()
function getName()

No comments: jQuery, Crockford

2.4 Array naming

Use plural form: Idiomatic

Copy code The code is as follows:

var documents = [];

No comments: Google, jQuery, NPM, Node.js, Crockford

2.5 Object and class naming

Use the following forms: Google, NPM, Node.js

Copy code The code is as follows:

var ThisIsObject = new Date;

No comments left: jQuery, Idiomatic, Crockford

2.6 Other naming

Use the all-lower-hyphen-css-case form for long filenames and configuration keys: NPM

3. Configure the .jshintrc file according to the above style

JSHint (http://www.jshint.com/) is a JavaScript syntax and style checking tool that you can use to alert you to code style-related issues. It can be integrated well into many commonly used editors and is a great tool to unify the team's coding style.

You can view the available options via the JSHint documentation: http://www.jshint.com/docs/#options
Next, create a .jshintrc file based on the first style under each of the above categories. You can put it in the root directory of the project, and the JSHint-avare code editor will follow it to unify all code styles in the project.

Copy code The code is as follows:

{
"camelcase" : true,
"indent": 2,
"undef": true,
"quotmark": single,
"maxlen": 80,
"trailing": true,
"curly": true
}

Additionally, you should add the following header to your JavaScript file:

Copy code The code is as follows:

/* jshint browser:true, jquery:true */

In the Node.js file you should add:

Copy code The code is as follows:

/*jshint node:true */

You can also add the following declaration to various JavaScript files:

Copy code The code is as follows:

'use strict';

This will affect JSHint and your JavaScript engine, which may be less compatible, but JavaScript will run faster.

4. Automatically execute JSHint before committing to Git

If you want to ensure that all JS code is consistent with the style defined in .jshintrc, you can add the following content to your .git/hooks/pre-commit file when you try to commit any new changes Style checking is automatically performed when files are added to the project.

Copy code The code is as follows:

#!/bin/bash
# Pre-commit Git hook to run JSHint on JavaScript files.
#
# If you absolutely must commit without testing,
# use: git commit --no-verify

filenames=($(git diff --cached --name-only HEAD))

which jshint &> /dev/null
if [ $? -ne 0 ];
then
echo "error: jshint not found"
echo "install with: sudo npm install -g jshint"
exit 1
fi

for i in "${filenames[@]}"
do
If [[ $i =~ .js$ ]];
Then
echo jshint $i
         jshint $i
           if [ $? -ne 0 ];
        then
exit 1
       fi
fi
done