jshint

What is jshint?

JSHint is a static code analysis tool used in software development for checking if JavaScript source code complies with coding rules. It helps developers identify potential errors and enforce coding standards.

What are jshint's main functionalities?

Basic Linting

This feature allows you to perform basic linting on a piece of JavaScript code. The code sample demonstrates how to use JSHint to check a simple JavaScript snippet for errors.

const jshint = require('jshint').JSHINT;
const code = 'var a = 1;';
const options = { esversion: 6 };
jshint(code, options);
console.log(jshint.errors);

Custom Configuration

JSHint allows you to customize the linting process with various options. This example shows how to enable the 'undef' option to check for the use of undefined variables.

const jshint = require('jshint').JSHINT;
const code = 'var a = 1;';
const options = { esversion: 6, undef: true };
jshint(code, options);
console.log(jshint.errors);

Using JSHint with Configuration File

You can use a configuration file (e.g., .jshintrc) to define your linting rules. This example demonstrates how to read a JavaScript file and a JSHint configuration file, then lint the code using the specified rules.

const fs = require('fs');
const jshint = require('jshint').JSHINT;
const code = fs.readFileSync('path/to/your/file.js', 'utf8');
const config = JSON.parse(fs.readFileSync('.jshintrc', 'utf8'));
jshint(code, config);
console.log(jshint.errors);

Other packages similar to jshint

eslint

ESLint is another popular JavaScript linting tool that is highly configurable and supports custom rules. It provides more flexibility and a larger ecosystem of plugins compared to JSHint.

jscs

JSCS (JavaScript Code Style) is a code style linter for JavaScript. It focuses more on enforcing coding style conventions rather than finding potential errors. It has been merged with ESLint, but older versions are still in use.

tslint

TSLint is a linter for TypeScript, which is a superset of JavaScript. It provides similar functionality to JSHint but is specifically designed for TypeScript code. TSLint is now deprecated in favor of ESLint with TypeScript support.

README

node-jshint

A command line interface and npm package for jshint.

Install

To use jshint from any location (for npm v1.x) you need to install using the global (-g) flag.

npm install -g jshint

Usage

jshint -h

You can also require JSHint itself as a module.

var jshint = require('jshint');

Note: If you are using npm v1.x be sure to install jshint locally (without the -g flag) or link it globally.

Text Editor Plugins

• gedit-node-jshint - Simply use CTRL+J in gedit to run JSHint using node-jshint.
• vim syntastic - Run node-jshint at each file save.
• sublime-jshint - F7 or command-B on any .js file. F4 next error line,column. shift-F4 previous error line,column.

Custom Reporters

Specify a custom reporter module (see example/reporter.js).

--reporter path/to/reporter.js

Use a jslint compatible xml reporter.

--jslint-reporter

Show additional non-error data generated by jshint (unused globals etc).

--show-non-errors

Configuration Options

Note: This behavior described below is very different from versions prior to 0.6.

The CLI uses the default options that come with JSHint.

Only one extra option is unique to node-jshint: globals allows you to define an object of globals that get ignored for every file. To see an example you can look at how whitelisted globals are defined in the jshint code

To have your own configuration apply, there are several methods you can use:

Specify Manually

Setting the --config=/path/to/your/config command line option to specify your own configuration file outside of the directory tree for your project.

Within your Project's Directory Tree

When the CLI is called, and a configuration file isn't specified already, node-jshint will attempt to locate one for you starting in pwd. (or "present working directory") If this does not yield a .jshintrc file, it will move one level up (..) the directory tree all the way up to the filesystem root. If a file is found, it stops immediately and uses that set of configuration.

This setup allows you to set up one configuration file for your entire project. (place it in the root folder) As long as you run jshint from anywhere within your project directory tree, the same configuration file will be used.

Home Directory

If all the methods above do not yield a .jshintrc to use, the last place that will be checked is your user's $HOME directory.

File Extensions

Default extension for files is ".js". If you want to use JSHint with other file extensions (.json), you need to pass this extra extension as an option :

--extra-ext .json

Ignoring Files and Directories

If there is a .jshintignore file in your project's directory tree, (also provided you run jshint from within your project's directory) then any directories or files specified will be skipped over. (behaves just like a .gitignore file)

Note: Pattern matching uses minimatch, with the nocase option. When there is no match, it performs a left side match (when no forward slashes present and path is a directory).

Installing dependencies for development

./configure

Build Commands

jake -T

Project Guidelines

• All tests are passing.
• No (new) JSHint errors are introduced.