jsPsych/plugins/jspsych-audio-button-response.js

/**
 * jspsych-audio-button-response
 * Kristin Diep
 *
 * plugin for playing an audio file and getting a keyboard response
 *
 * documentation: docs.jspsych.org
 *
 **/

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.'
      },
      response_allowed_while_playing: {
        type: jsPsych.plugins.parameterType.BOOL,
        pretty_name: 'Response allowed while playing',
        default: true,
        description: 'If true, then responses are allowed while the audio is playing. ' +
          'If false, then the audio must finish playing before a response is accepted.'
      }
    }
  }

  plugin.trial = function (display_element, trial) {

    // setup stimulus
    var context = jsPsych.pluginAPI.audioContext();
    var audio;

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

    // record webaudio context start time
    var startTime;

    // load audio file
    jsPsych.pluginAPI.getAudioBuffer(trial.stimulus)
      .then(function (buffer) {
        if (context !== null) {
          audio = context.createBufferSource();
          audio.buffer = buffer;
          audio.connect(context.destination);
        } else {
          audio = buffer;
          audio.currentTime = 0;
        }
        setupTrial();
      })
      .catch(function (err) {
        console.error(`Failed to load audio file "${trial.stimulus}". Try checking the file path. We recommend using the preload plugin to load audio files.`)
        console.error(err)
      });

    function setupTrial() {
      // set up end event if trial needs it
      if (trial.trial_ends_after_audio) {
        audio.addEventListener('ended', end_trial);
      }

      // enable buttons after audio ends if necessary
      if ((!trial.response_allowed_while_playing) & (!trial.trial_ends_after_audio)) {
        audio.addEventListener('ended', enable_buttons);
      }

      //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 audio-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;

      if (trial.response_allowed_while_playing) {
        enable_buttons();
      } else {
        disable_buttons();
      }

      // start time
      startTime = performance.now();

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



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

      // measure rt
      var endTime = performance.now();
      var rt = endTime - startTime;
      if (context !== null) {
        endTime = context.currentTime;
        rt = Math.round((endTime - startTime) * 1000);
      }
      response.button = parseInt(choice);
      response.rt = rt;

      // disable all the buttons after a response
      disable_buttons();

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

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

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

      // stop the audio file if it is playing
      // remove end event listeners if they exist
      if (context !== null) {
        audio.stop();
      } else {
        audio.pause();
      }

      audio.removeEventListener('ended', end_trial);
      audio.removeEventListener('ended', enable_buttons);

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

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

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

    function button_response(e) {
      var choice = e.currentTarget.getAttribute('data-choice'); // don't use dataset for jsdom compatibility
      after_response(choice);
    }

    function disable_buttons() {
      var btns = document.querySelectorAll('.jspsych-audio-button-response-button');
      for (var i = 0; i < btns.length; i++) {
        var btn_el = btns[i].querySelector('button');
        if (btn_el) {
          btn_el.disabled = true;
        }
        btns[i].removeEventListener('click', button_response);
      }
    }

    function enable_buttons() {
      var btns = document.querySelectorAll('.jspsych-audio-button-response-button');
      for (var i = 0; i < btns.length; i++) {
        var btn_el = btns[i].querySelector('button');
        if (btn_el) {
          btn_el.disabled = false;
        }
        btns[i].addEventListener('click', button_response);
      }
    }



  };

  return plugin;
})();