module.autoPreload = function()

in datawig-js/static/jspsych-6.1.0/jspsych.js [2504:2573]

• 50 lines of code
• 18 McCabe index (conditional complexity)

  module.autoPreload = function(timeline, callback, images, audio, video, progress_bar) {
    // list of items to preload
    images = images || [];
    audio = audio || [];
    video = video || [];

    // construct list
    for (var i = 0; i < preloads.length; i++) {
      var type = preloads[i].plugin;
      var param = preloads[i].parameter;
      var media = preloads[i].media_type;
      var func = preloads[i].conditional_function;
      var trials = timeline.trialsOfType(type);
      for (var j = 0; j < trials.length; j++) {

        if (trials[j][param] && typeof trials[j][param] !== 'function') {

          if ( !func  || func(trials[j]) ){
            if (media === 'image') {
              images = images.concat(jsPsych.utils.flatten([trials[j][param]]));
            } else if (media === 'audio') {
              audio = audio.concat(jsPsych.utils.flatten([trials[j][param]]));
            }
            else if (media === 'video') {
              video = video.concat(jsPsych.utils.flatten([trials[j][param]]));
            }
          }
        }
      }
    }

    images = jsPsych.utils.unique(jsPsych.utils.flatten(images));
    audio  = jsPsych.utils.unique(jsPsych.utils.flatten(audio));
    video  = jsPsych.utils.unique(jsPsych.utils.flatten(video));

    // remove any nulls false values
    images = images.filter(function(x) { return x != false && x != null})
    audio = audio.filter(function(x) { return x != false && x != null})
    video = video.filter(function(x) { return x != false && x != null})
    
    var total_n = images.length + audio.length + video.length;

    var loaded = 0;

    if(progress_bar){
      var pb_html = "<div id='jspsych-loading-progress-bar-container' style='height: 10px; width: 300px; background-color: #ddd;'>";
      pb_html += "<div id='jspsych-loading-progress-bar' style='height: 10px; width: 0%; background-color: #777;'></div>";
      pb_html += "</div>";
      jsPsych.getDisplayElement().innerHTML = pb_html;
    }

    function update_loading_progress_bar(){
      loaded++;
      if(progress_bar){
        var percent_loaded = (loaded/total_n)*100;
        jsPsych.getDisplayElement().querySelector('#jspsych-loading-progress-bar').style.width = percent_loaded+"%";
      }
    }

    // do the preloading
    // first the images, then when the images are complete
    // wait for the audio files to finish
    module.preloadImages(images, function() {
      module.preloadAudioFiles(audio, function() {
          module.preloadVideo(video, function() {
              callback();
          }, update_loading_progress_bar);
      }, update_loading_progress_bar);
    }, update_loading_progress_bar);
  }