@xiangnanscu/lua2js

@xiangnanscu/lua2js transform lua to js literally.

Install

npm install -g @xiangnanscu/lua2js

Usage

command

Concat one or more js files and transform them to one lua string:

lua2js [options] file1, file2, ...

where options are:

const defaultOptions = {
  printToConsoleLog: true,
  tryUseOfLoop: true,
  indexMinusOne: true,
  returnNilToThrow: true,
  errorToThrow: true,
  tostring: true,
  dict: true,
  list: true,
  unpack: true,
  tonumber: true,
  class: true,
  selfToThis: true,
  clsToThis: true,
  typeToTypeof: true,
  stringFormat: true,
  tableConcat: true,
  tableInsert: true,
  camelStyle: false,
};

Options Details

printToConsoleLog

Default: true
Convert print to console.log.

Input Lua:

print("hello world")

Output JS (Default):

console.log("hello world");

tryUseOfLoop

Default: true
Try to use for...of loop for ipairs or pairs when the index is not used.

Input Lua:

for i, v in ipairs(t) do
    print(v)
end

Output JS (Default):

for (let v of t) {
  console.log(v);
}

indexMinusOne

Default: true
Decrement numeric index by 1 (Lua is 1-based, JS is 0-based).

Input Lua:

a = t[1]

Output JS (Default):

a = t[0];

returnNilToThrow

Default: true
Convert return nil, err to throw new Error(err).

Input Lua:

return nil, "error message"

Output JS (Default):

throw new Error("error message");

errorToThrow

Default: true
Convert error(msg) to throw new Error(msg).

Input Lua:

error("something wrong")

Output JS (Default):

throw new Error("something wrong");

tostring

Default: true
Convert tostring(x) to String(x).

Input Lua:

s = tostring(123)

Output JS (Default):

let s = String(123);

dict

Default: true
Convert dict(t) calls (or utils.dict) to object spread syntax.

Input Lua:

d = dict(t)

Output JS (Default):

let d = { ...t };

list

Default: true
Convert list(t) calls (or utils.list) to array spread syntax.

Input Lua:

l = list(t)

Output JS (Default):

let l = [...t];

unpack

Default: true
Convert unpack(t) to spread syntax ...t.

Input Lua:

f(unpack(t))

Output JS (Default):

f(...t);

tonumber

Default: true
Convert tonumber(x) to Number(x).

Input Lua:

n = tonumber("123")

Output JS (Default):

let n = Number("123");

class

Default: true
Enable class syntax transformation for class "Name" or class(Base).

Input Lua:

class "Person"

Output JS (Default):

class Person {}

selfToThis

Default: true
Convert self to this in methods.

Input Lua:

function Person:say()
    print(self.name)
end

Output JS (Default):

Person.prototype.say = function () {
  console.log(this.name);
};

clsToThis

Default: true
Convert cls to this in static methods.

Input Lua:

function Person.create(cls)
    return cls()
end

Output JS (Default):

Person.create = function () {
  return new this();
};

typeToTypeof

Default: true
Convert type(x) to typeof(x).

Input Lua:

t = type(x)

Output JS (Default):

let t = typeof x;

stringFormat

Default: true
Convert string.format to template literals (when using %s).

Input Lua:

s = string.format("hello %s", name)

Output JS (Default):

let s = `hello ${name}`;

tableConcat

Default: true
Convert table.concat to .join.

Input Lua:

s = table.concat(t, ",")

Output JS (Default):

let s = t.join(",");

tableInsert

Default: true
Convert table.insert to .push or .unshift.

Input Lua:

table.insert(t, v)
table.insert(t, 1, v)

Output JS (Default):

t.push(v);
t.unshift(v);

camelStyle

Default: false
Convert snake_case variables to camelCase.

Input Lua:

local my_variable = 1

Output JS (with --camelStyle):

let myVariable = 1;

examples

Basic:

lua2js foo.lua > foo.js

To disable a feature --no-[option]:

lua2js --no-camelStyle foo.lua

To enable a feature --[option]:

lua2js --camelStyle foo.lua

api

import { lua2js } from "lua2js";

const jscode = lua2js(`local snake_var = 1`, { camelStyle: true });
// let snakeVar = 1;

see also

@xiangnanscu/js2lua transform js to lua

todo