Luxe/Flow Hooks Example

stisa, Oct 2, 2015

I’m playing around with luxe, building a simple depth first search-based maze generator, which I plan on turning into a full game ( btw you can try it here ).
While iterating, I had to copy-paste the content of bin/web/ to the folder linked with the project git repo, but it got old fast, and I had to find a faster way.
At first, I tried using the --output-path <path> flag in flow, that overrides the flow tree path. The problem with this method is that flow generates two folders, web and, inside your selected path, and I didn’t like it very much.
That’s when I found out about hooks, digging trough flow source code.


flow has the ability of launching node.js scripts before ( pre ) and after ( post ) building and running your project.
This gave me the option of using a simple script to copy the output of the build to another folder, without having to copy-paste manually every time.

To use hooks, you have to add them to your project.flow :

  build : {
    dependencies : {
      //your dependencies
    post : {  
      priority : 1,
      name : 'copy-to-gh-pages',
      desc : 'copy bin/web to gh-pages',
      script : './hooks/post.js',

Then you have to write your script, in my case post.js:

  var fs = require('fs-extra');
  var path = require('path');

  exports.hook = function(flow, done){
    // generic json reading function
    function read_json (file_path) {
        var temp;
        temp = fs.readFileSync(path.resolve(file_path));
        return JSON.parse(temp);

    //read our config file
    var config_file = "./hooks/config.json";

    var config = read_json(config_file);
    var dirs = config.dirs;

    console.log("copy-to-gh-pages - Source dir: "+ dirs.bin+", Target dir: "+ dirs.gh_pages);
    fs.copy(dirs.bin,dirs.gh_pages, function copy_site(err){
      if (err) throw err;
      console.log("copy-to-gh-pages - Project copied");
      console.log("copy-to-gh-pages - Copying git_files...");
      fs.readdir(dirs.git_files,function copy_git_files(err,files){
        if (err) throw err;
        for (var i = 0; i<files.length;i++) {
          var file = files[i];
          console.log("copy-to-gh-pages -  Copied "+file);
          fs.copy(path.join(dirs.git_files,file),path.join(dirs.gh_pages,file), function copy_file(err){
            if (err) throw err;
        } // for

      })  // readdir
    })   // copy

The important bits here are :

  exports.hook = function(flow, done){
    // do something here...

    // when you're finished, just say it:


The exports.hook part allows flow to call our hook, passing it a flow object and the done function.
Calling done() signals the build tool that our script is finished executing and that it can go on.

And that’s it, just flow run <target> your project and watch as your hook does its thing.

Thanks for reading this, and if you find errors or if I got something wrong, please open an issue on github


  • flow
  • hooks
  • luxe
  • example
  • haxe