Love.js-Api-Player

Created as a binder between love.js and javascript, it is made to be able to call javascript functions from lua code

How it works

• It wraps the window.console logging function, and it eval's the string passed as a JS function, it still mantains the correct functionality from the old console, unless passing the key string to it, it will not log into the devtools console, as it should just execute it
• BEWARE: There are some sites that doesn't let you wrap their console, if you're not able doing, the API won't work

How to

• Download js.lua file
• Add the following lua function to your main.lua

require 'js'

• Convert your project to love.js, all thanks to TannerRogalsky
• Add the <script src = "consolewrapper.js"></script> to the index.html file created by the love.js conversion
• After that, for a simple JS call, where you don't expect any return value, call:

JS.callJS('kongregate.stats.submit("Score", 1000);')

Executing Javascript code block

It is possible to execute js code block, but you will need to call another function with JS.callJS:

JS.callJS(JS.stringFunc(
    [[
        var test = 5;
        test+= 15;
        console.log(test);
    ]]
))

Code blocks also supports formatted characters for easy passing parameters inside your code:

JS.callJS(JS.stringFunc(
    [[
        console.log("stringFromJS "+ "%s");
    ]]
, "stringFromLua")

Please, note that code blocks doesn't support Javascript comments

• However, if you do wish to retrieve the value from the JS Api Call, it is a bit more complicated, you will need to use the full extent of js.lua:

Setting up for data retrieve

1. After importing js.lua file, call JS.newRequest(strApiToCallInJS, closureOnSuccess)

   1. strApiToCallInJS: a string of the api you want to call
   2. closureOnSuccess: A function to call when the data arrives

2. For retrieving your data, you must set it as a closure, kongregate has one api for getting the player username: kongregate is: kongregate.services.getUsername(), so let's try showing how we can get the data:

   gUsername = ""
   JS.newRequest('kongregate.services.getUsername()', 
   function(data)
       gUsername = data
   end)

   1. If you wish to retrieve data from a code block, simply return from the code block

       JS.newRequest(JS.stringFunc(
           [[
               var test = 5;
               return test + 15;
           ]]
       ))

3. This will make the request active, and it will store in the indexed database, for actually completing the request, you must choose if you want it to be sync or assync, in this example, I'm going to show the sync one:

   1. In love.update, make it the first line:

   if(JS.retrieveData(dt)) then
       return
   end

   2. This function will return wether if it is still trying to retrieve or not, so, returning will make the game don't update
   3. After that, you're set up for using the lib

Handling promises for data retrieving

This lib can be quite powerful if you understood how to use it, for handling promises, there is 2 ways possible

1. From Javascript code

If you wish to call a Javascript function that will set the data for you, you will need to call a function that will receive(or set) your save path and your id:

    JS.newPromiseRequest("myJsFunc('"..love.filesystem.getSaveDirectory().."', '"..myLuaId.."');", onDataLoaded, onError, timeout, myLuaId)

This will trigger your function, but Lua won't recognize it has loaded the data, for recognizing it, you will need to call in your JS code onload data callback (usually inside Promise.resolve):

    FS.writeFile(luaSaveDir+"/__temp"+luaId, myResolvedPromiseData);

Always remember passing "/__temp" with your luaId to your saveDir Passing "ERROR" into your myResolvedPromiseData will return as an error in your lua code, this is how you catch errors, you can put additional data for better error handling

2. From Lua code

If instead you wish to resolve promises inside your own lua code, it is quite simple (although not as flexible when handling from JS):

JS.newPromiseRequest(JS.stringFunc(
    [[
        var xhttp = new XMLHttpRequest();
        xhttp.onreadystatechange = function()
        {    
            if (this.readyState == 4 && this.status == 200)
                _$_(this.responseText);
        };
        xhttp.open("GET", "https://example.com", true);
        xhttp.send();
    ]]

With this piece of code, we can directly use _$_ as a function to load data insided Lua, $ is a syntactic sugar for:

[[ FS.writeFile("%s", this.responseText) ]]:format(love.filesystem.getSaveDirectory().."/__temp"..promiseRequestId)

So, prefer using it, as you can see, it reduces much written code

Integration with Davidobot lovejs

Davidobot's fork' has some differences from the TannerRogalsky's one. There is a file in which is able to fix the difference about saving onto the file system (which is how the api player works). This file is globalizeFS.js.

It is a nodejs based solution for actually saving the Davidobot's FS into the global scope for the Lua being able to actually execute it. Integrate it with your build for love.js. After outputting the love.js file, execute node globalizeFS.js. It will automatically replace the correct lines with the necessary code.

EXTRA

1. In lib, it is available too some error handlers, those error occurs only when the retrieveData nevers return, the default value for timeout is 2, but you can change it at your taste
2. JS.newRequest accepts 3 more parameters, the full definition is: JS.newRequest(funcToCall, onDataLoaded, onError, timeout, optionalId), onError is a function that receives the requestID, timeout is a custom parameter for setting if you want to have increased or decreased timeout value, the optionalId is called optional because it will be setup as an incrementing number, but if you want, you can pass a string value for identifying errors
3. There is another function called JS.setDefaultErrorFunction, by setting it up, when your retrieveData returns an error, the function set on the defaultError will be called, there is one already that prints the id of the request if the debug is active

Working Example

• Here is the probably first ever love2d-kongregate integrated game: https://www.kongregate.com/games/MrcSnm/industrial-flying-creature