core.init = function()

in datawig-js/static/jspsych-6.1.0/jspsych.js [54:201]
76 lines of code
8 McCabe index (conditional complexity)

  core.init = function(options) {

    if(typeof options.timeline === 'undefined'){
      console.error('No timeline declared in jsPsych.init. Cannot start experiment.')
    }

    // reset variables
    timeline = null;
    global_trial_index = 0;
    current_trial = {};
    current_trial_finished = false;
    paused = false;
    waiting = false;
    loaded = false;
    loadfail = false;
    jsPsych.data.reset();

    var defaults = {
      'display_element': undefined,
      'on_finish': function(data) {
        return undefined;
      },
      'on_trial_start': function(trial) {
        return undefined;
      },
      'on_trial_finish': function() {
        return undefined;
      },
      'on_data_update': function(data) {
        return undefined;
      },
      'on_interaction_data_update': function(data){
        return undefined;
      },
      'on_close': function(){
        return undefined;
      },
      'preload_images': [],
      'preload_audio': [],
      'preload_video': [],
      'use_webaudio': true,
      'exclusions': {},
      'show_progress_bar': false,
      'message_progress_bar': 'Completion Progress',
      'auto_update_progress_bar': true,
      'auto_preload': true,
      'show_preload_progress_bar': true,
      'max_load_time': 60000,
      'max_preload_attempts': 10,
      'default_iti': 0,
      'experiment_width': null
    };

    // override default options if user specifies an option
    opts = Object.assign({}, defaults, options);

    // set DOM element where jsPsych will render content
    // if undefined, then jsPsych will use the <body> tag and the entire page
    if(typeof opts.display_element == 'undefined'){
      // check if there is a body element on the page
      var body = document.querySelector('body');
      if (body === null) {
        document.documentElement.appendChild(document.createElement('body'));
      }
      // using the full page, so we need the HTML element to
      // have 100% height, and body to be full width and height with
      // no margin
      document.querySelector('html').style.height = '100%';
      document.querySelector('body').style.margin = '0px';
      document.querySelector('body').style.height = '100%';
      document.querySelector('body').style.width = '100%';
      opts.display_element = document.querySelector('body');
    } else {
      // make sure that the display element exists on the page
      var display;
      if (opts.display_element instanceof Element) {
        var display = opts.display_element;
      } else {
        var display = document.querySelector('#' + opts.display_element);
      }
      if(display === null) {
        console.error('The display_element specified in jsPsych.init() does not exist in the DOM.');
      } else {
        opts.display_element = display;
      }
    }
    opts.display_element.innerHTML = '<div class="jspsych-content-wrapper"><div id="jspsych-content"></div></div>';
    DOM_container = opts.display_element;
    DOM_target = document.querySelector('#jspsych-content');
    

    // add tabIndex attribute to scope event listeners
    opts.display_element.tabIndex = 0;

    // add CSS class to DOM_target
    if(opts.display_element.className.indexOf('jspsych-display-element') == -1){
      opts.display_element.className += ' jspsych-display-element';
    }
    DOM_target.className += 'jspsych-content';

    // set experiment_width if not null
    if(opts.experiment_width !== null){
      DOM_target.style.width = opts.experiment_width + "px";
    }

    // create experiment timeline
    timeline = new TimelineNode({
      timeline: opts.timeline
    });

    // initialize audio context based on options and browser capabilities
    jsPsych.pluginAPI.initAudio();

    // below code resets event listeners that may have lingered from
    // a previous incomplete experiment loaded in same DOM.
    jsPsych.pluginAPI.reset(opts.display_element);
    // create keyboard event listeners
    jsPsych.pluginAPI.createKeyboardEventListeners(opts.display_element);
    // create listeners for user browser interaction
    jsPsych.data.createInteractionListeners();

    // add event for closing window
    window.addEventListener('beforeunload', opts.on_close);

    // check exclusions before continuing
    checkExclusions(opts.exclusions,
      function(){
        // success! user can continue...
        // start experiment, with or without preloading
        if(opts.auto_preload){
          jsPsych.pluginAPI.autoPreload(timeline, startExperiment, opts.preload_images, opts.preload_audio, opts.preload_video, opts.show_preload_progress_bar);
          if(opts.max_load_time > 0){
            setTimeout(function(){
              if(!loaded && !loadfail){
                core.loadFail();
              }
            }, opts.max_load_time);
          }
        } else {
          startExperiment();
        }
      },
      function(){
        // fail. incompatible user.

      }
    );
  };