Running karma js with rails asset pipeline / sprockets

# test/karma.conf.js
...
    basePath: '<%= Bundler.root %>',
...
    files: [
      '<%= resolve_asset('vis.js') %>',
      'app/assets/javascripts/app.js',
      'test/**/*_spec.js'
    ],

# Rakefile
namespace :test do
  task js: :environment do
    with_tmp_karma_config do |config|
      sh "./node_modules/karma/bin/karma start #{config} --single-run"
    end
  end

  private

  def with_tmp_karma_config
    Tempfile.open('karma.js') do |f|
      f.write ERB.new(File.read('test/karma.conf.js')).result(binding)
      f.flush
      yield f.path
    end
  end

  def resolve_asset(file)
    Rails.application.assets.find_asset(file).to_a.first.pathname.to_s
  end
end

Refile upload with jquery-ui and progress

Ran into a few gotschas while implementing this, so I wanted to share 🙂

– buttons need to be disabled via the button method
– e.originalEvent.detail holds progress information


$(document).on("upload:start", "form", function(e) {
  $(e.target).prev().prev('img').hide(); // hide old image we are replacing
  $(this).find("input[type=submit]").
    button({disabled: true}). // do not let user press submit until image is uploaded
    after('<img src="/images/loading.gif" />') // indicate we are waiting
});

$(document).on("upload:progress", "form", function(e) {
  // http://stackoverflow.com/questions/10420352/converting-file-size-in-bytes-to-human-readable
  function humanFileSize(bytes) {
    var thresh = 1024;
    if(bytes < thresh) return bytes + ' B';
    var units = ['kB','MB','GB','TB','PB','EB','ZB','YB'];
    var u = -1;
    do {
      bytes /= thresh;
      ++u;
    } while(bytes >= thresh);
    return bytes.toFixed(1)+' '+units[u];
  };

  var detail = e.originalEvent.detail;
  var percentage = Math.round((detail.loaded / detail.total) * 100);
  $(e.target).next().text(percentage + "% of " + humanFileSize(detail.total))
});

$(document).on("upload:complete", "form", function(e) {
  if(!$(this).find("input.uploading").length) {
    $(this).find("input[type=submit]").
      button({disabled: false}). // all images uploaded, user can submit the form
      next().remove(); // remove loading
  }
});

Development checks for fast boottime

A few simple checks to make sure we are not regressing into slow boot times by preloading to many things. Needs to be the last initializer so it catches what all the others are doing -> zz.rb

Code

# config/initializers/zz.rb
if Rails.env.development?
  # make sure we do not regress into slow startup time by preloading to much
  Rails.configuration.after_initialize do
    [
      ActiveRecord::Base.send(:descendants).map(&:name),
      ActionController::Base.descendants.map(&:name),
      (File.basename($0) != "rake" && defined?(Rake) && "rake"),
    ].compact.flatten.each { |c| raise "#{c} should not be loaded" }
  end
end

Result

config/initializers/zz.rb:9:in `block (2 levels) in ': 
User should not be loaded (RuntimeError)