Luacheck-browserify

Luacheck is a static analyzer and a linter for Lua. Luacheck detects various issues such as usage of undefined global variables, unused variables and values, accessing uninitialized variables, unreachable code and more. Most aspects of checking are configurable: there are options for defining custom project-related globals, for selecting set of standard globals (version of Lua standard library), for filtering warnings by type and name of related variable, etc.

Luacheck supports checking Lua files using syntax of Lua 5.1 - 5.4, and LuaJIT. Luacheck itself is written in Lua and runs on all of mentioned Lua versions.

Luacheck-browserify is a fork of Luacheck that has been modified to work in browser environments. The Lua code is executed using Wasmoon. Luacheck-browserify can also be specifically configured to check Lua modules in MediaWiki sites.

Contents

• Installation
• Basic usage
  • Class instance methods
  • Static method
• Related projects
• Documentation

Installation

As a NPM package, Luacheck-browserify can be included in a project using a CDN. Add the following script tag to the HTML file:

<script src="https://cdn.jsdelivr.net/npm/luacheck-browserify"></script>

or

<script src="https://unpkg.com/luacheck-browserify"></script>

Basic usage

After Luacheck-browserify is installed, a global async function luacheck is available. The luacheck function takes a required second argument which is one of the following:

• a string to specify the standard globals similar to the --std CLI option;

const Luacheck = luacheck('max');

• a JavaScript object to specify a custom set of globals;

const Luacheck = luacheck({
	globals: ['foo', 'bar'],
	read_globals: ['baz'],
});

• a Luacheck configuration object that must contain a std key. This is especially useful for filtering warnings by warning codes and/or variable names.

const Luacheck = luacheck({std: 'max'});

In addition to the standard globals provided by Luacheck (e.g., lua53 for Lua 5.3), Luacheck-browserify also supports mediawiki for MediaWiki-specific globals implemented in the Scribunto extension.

Class instance methods

The luacheck function returns a class instance with an async queue method that can be called with a string of Lua code to check. The queue method returns a promise that resolves with an array of warnings.

const Luacheck = luacheck('max');
console.log(await Luacheck.queue('local a, b, c = nil'));

The setConfig method of the class instance can be used to dynamically configure the checker.

const Luacheck = luacheck('max');
Luacheck.setConfig('lua55c');

Static method

Otherwise, the luacheck.check static method can be called with a string of Lua code and specified standard globals or Luacheck configuration object to return a promise that resolves with an array of warnings.

console.log(await luacheck.check('local a, b, c = nil', 'lua55c'));

console.log(await luacheck.check('local a, b, c = nil', {
	globals: ['foo', 'bar'],
	read_globals: ['baz'],
}));

console.log(await luacheck.check('local a, b, c = nil', {std: 'lua55c'}));

The warnings are objects with the following properties:

interface {
	line: number;
	column: number;
	end_column: number;
	code: string;
	msg: string;
	/** 0: info, 1: warning, 2: error */
	severity: 0 | 1 | 2;
}

For more info about the warnings, see Luacheck documentation.

Related projects

There are a few plugins which allow using Luacheck directly inside an editor, showing warnings inline:

• For CodeMirror, CodeMirror-MediaWiki contains luacheck checker (Demo).
• For Monaco editor, Monaco-Wiki contains luacheck checker (Demo).

Documentation

Luacheck Documentation is available online.