plugin-module.js

/**
 * jspsych-audio-button-response
 * Kristin Diep
 *
 * plugin for playing an audio file and getting a keyboard response
 *
 * documentation: docs.jspsych.org
 *
 **/
 var loader = function(jsPsych) {
  jsPsych.plugins["audio-button-response"] = (function() {
    var plugin = {};

    jsPsych.pluginAPI.registerPreload('audio-button-response', 'stimulus', 'audio');

    plugin.info = {
      name: 'audio-button-response',
      description: '',
      parameters: {
        stimulus: {
          type: jsPsych.plugins.parameterType.AUDIO,
          pretty_name: 'Stimulus',
          default: undefined,
          description: 'The audio to be played.'
        },
        choices: {
          type: jsPsych.plugins.parameterType.STRING,
          pretty_name: 'Choices',
          default: undefined,
          array: true,
          description: 'The button labels.'
        },
        button_html: {
          type: jsPsych.plugins.parameterType.HTML_STRING,
          pretty_name: 'Button HTML',
          default: '<button class="jspsych-btn">%choice%</button>',
          array: true,
          description: 'Custom button. Can make your own style.'
        },
        prompt: {
          type: jsPsych.plugins.parameterType.STRING,
          pretty_name: 'Prompt',
          default: null,
          description: 'Any content here will be displayed below the stimulus.'
        },
        trial_duration: {
          type: jsPsych.plugins.parameterType.INT,
          pretty_name: 'Trial duration',
          default: null,
          description: 'The maximum duration to wait for a response.'
        },
        margin_vertical: {
          type: jsPsych.plugins.parameterType.STRING,
          pretty_name: 'Margin vertical',
          default: '0px',
          description: 'Vertical margin of button.'
        },
        margin_horizontal: {
          type: jsPsych.plugins.parameterType.STRING,
          pretty_name: 'Margin horizontal',
          default: '8px',
          description: 'Horizontal margin of button.'
        },
        response_ends_trial: {
          type: jsPsych.plugins.parameterType.BOOL,
          pretty_name: 'Response ends trial',
          default: true,
          description: 'If true, the trial will end when user makes a response.'
        },
        trial_ends_after_audio: {
          type: jsPsych.plugins.parameterType.BOOL,
          pretty_name: 'Trial ends after audio',
          default: false,
          description: 'If true, then the trial will end as soon as the audio file finishes playing.'
        },
      }
    }

    plugin.trial = function(display_element, trial) {

      // setup stimulus
      var context = jsPsych.pluginAPI.audioContext();
      if(context !== null){
        var source = context.createBufferSource();
        source.buffer = jsPsych.pluginAPI.getAudioBuffer(trial.stimulus);
        source.connect(context.destination);
      } else {
        var audio = jsPsych.pluginAPI.getAudioBuffer(trial.stimulus);
        audio.currentTime = 0;
      }

      // set up end event if trial needs it
      if(trial.trial_ends_after_audio){
        if(context !== null){
          source.onended = function() {
            end_trial();
          }
        } else {
          audio.addEventListener('ended', end_trial);
        }
      }

      //display buttons
      var buttons = [];
      if (Array.isArray(trial.button_html)) {
        if (trial.button_html.length == trial.choices.length) {
          buttons = trial.button_html;
        } else {
          console.error('Error in image-button-response plugin. The length of the button_html array does not equal the length of the choices array');
        }
      } else {
        for (var i = 0; i < trial.choices.length; i++) {
          buttons.push(trial.button_html);
        }
      }

      var html = '<div id="jspsych-audio-button-response-btngroup">';
      for (var i = 0; i < trial.choices.length; i++) {
        var str = buttons[i].replace(/%choice%/g, trial.choices[i]);
        html += '<div class="jspsych-audio-button-response-button" style="cursor: pointer; display: inline-block; margin:'+trial.margin_vertical+' '+trial.margin_horizontal+'" id="jspsych-audio-button-response-button-' + i +'" data-choice="'+i+'">'+str+'</div>';
      }
      html += '</div>';

      //show prompt if there is one
      if (trial.prompt !== null) {
        html += trial.prompt;
      }

      display_element.innerHTML = html;

      for (var i = 0; i < trial.choices.length; i++) {
        display_element.querySelector('#jspsych-audio-button-response-button-' + i).addEventListener('click', function(e){
          var choice = e.currentTarget.getAttribute('data-choice'); // don't use dataset for jsdom compatibility
          after_response(choice);
        });
      }

      // store response
      var response = {
        rt: null,
        button: null
      };

      // function to handle responses by the subject
      function after_response(choice) {

        // measure rt
        var end_time = Date.now();
        var rt = end_time - start_time;
        response.button = choice;
        response.rt = rt;

        // disable all the buttons after a response
        var btns = document.querySelectorAll('.jspsych-audio-button-response-button button');
        for(var i=0; i<btns.length; i++){
          //btns[i].removeEventListener('click');
          btns[i].setAttribute('disabled', 'disabled');
        }

        if (trial.response_ends_trial) {
          end_trial();
        }
      };

      // function to end trial when it is time
      function end_trial() {

        // stop the audio file if it is playing
        // remove end event listeners if they exist
        if(context !== null){
          source.stop();
          source.onended = function() { }
        } else {
          audio.pause();
          audio.removeEventListener('ended', end_trial);
        }

        // kill any remaining setTimeout handlers
        jsPsych.pluginAPI.clearAllTimeouts();

        // gather the data to store for the trial
        var trial_data = {
          "rt": response.rt,
          "stimulus": trial.stimulus,
          "button_pressed": response.button
        };

        // clear the display
        display_element.innerHTML = '';

        // move on to the next trial
        jsPsych.finishTrial(trial_data);
      };

      // start time
      var start_time = Date.now();

      // start audio
      if(context !== null){
        startTime = context.currentTime;
        source.start(startTime);
      } else {
        audio.play();
      }

      // end trial if time limit is set
      if (trial.trial_duration !== null) {
        jsPsych.pluginAPI.setTimeout(function() {
          end_trial();
        }, trial.trial_duration);
      }

    };

    return plugin;
  }());

}


(function (root, factory) {
  if(typeof define === "function" && define.amd) {
     define([], factory);
  } else if(typeof module === "object" && module.exports) {
     module.exports = factory;
  } else {
     factory(this.jsPsych);
  }
}(this, loader));