jsPsych/plugins/jspsych-multi-stim-multi-response.js

/**
* jspsych-muli-stim-multi-response
* Josh de Leeuw
*
* plugin for displaying a set of stimuli and collecting a set of responses
* via the keyboard
*
* documentation: docs.jspsych.org
*
**/

(function($) {
	jsPsych["multi-stim-multi-response"] = (function() {

		var plugin = {};

		plugin.create = function(params) {

			var trials = new Array(params.stimuli.length);

			for (var i = 0; i < trials.length; i++) {
				trials[i] = {};
				trials[i].stimuli = params.stimuli[i];
				trials[i].choices = params.choices;
				// option to show image for fixed time interval, ignoring key responses
				//      true = image will keep displaying after response
				//      false = trial will immediately advance when response is recorded
				trials[i].continue_after_response = (typeof params.continue_after_response === 'undefined') ? true : params.continue_after_response;
				// timing parameters
				var default_timing_array = [];
				for(var i = 0; i < params.stimuli[i].length; i++){
					default_timing_array.push(1000);
				}
				trials[i].timing_stim = params.timing_stim || default_timing_array; 
				trials[i].timing_response = params.timing_response || -1; // if -1, then wait for response forever
				// optional parameters
				trials[i].is_html = (typeof params.is_html === 'undefined') ? false : params.is_html;
				trials[i].prompt = (typeof params.prompt === 'undefined') ? "" : params.prompt;
			}
			return trials;
		};



		plugin.trial = function(display_element, trial) {

			// if any trial variables are functions
			// this evaluates the function and replaces
			// it with the output of the function
			trial = jsPsych.pluginAPI.normalizeTrialVariables(trial);

			// this array holds handlers from setTimeout calls
			// that need to be cleared if the trial ends early
			var setTimeoutHandlers = [];

			// array to store if we have gotten a valid response for
			// all the different response types
			var validResponses = [];
			for(var i = 0; i < trial.choices.length; i++){
				validResponses[i] = false;
			}

			// array for response times for each of the different response types
			var responseTimes = [];
			for(var i = 0; i < trial.choices.length; i++){
				responseTimes[i] = -1;
			}

			// array for response keys for each of the different response types
			var responseKeys = [];
			for(var i = 0; i < trial.choices.length; i++){
				responseKeys[i] = -1;
			}

			// function to check if all of the valid responses are received
			function checkAllResponsesAreValid(){
				for(var i = 0; i<validResponses.length; i++){
					if(validResponses[i] == false){
						return false;
					}
				}
				return true;
			}

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

				// kill any remaining setTimeout handlers
				for (var i = 0; i < setTimeoutHandlers.length; i++) {
					clearTimeout(setTimeoutHandlers[i]);
				}

				// kill keyboard listeners
				jsPsych.pluginAPI.cancelKeyboardResponse(keyboardListener);

				// gather the data to store for the trial
				var trial_data = {
					"rt": JSON.stringify(responseTimes),
					"stimulus": JSON.stringify(trial.stimuli),
					"key_press": JSON.stringify(responseKeys)
				};

				jsPsych.data.write($.extend({}, trial_data, trial.data));

				// clear the display
				display_element.html('');

				// move on to the next trial
				if (trial.timing_post_trial > 0) {
					setTimeout(function() {
						jsPsych.finishTrial();
					}, trial.timing_post_trial);
				} else {
					jsPsych.finishTrial();
				}
			};

			// function to handle responses by the subject
			var after_response = function(info) {

				var whichResponse;
				for(var i = 0; i<trial.choices.length; i++){
					// TODO: this method will only work if keys are specified
					// as key codes. Generalize to characters.
					if(trial.choices[i].indexOf(info.key) > -1){
						whichResponse = i;
						break;
					}
				}

				if(validResponses[whichResponse] != true){
					validResponses[whichResponse] = true;
					responseTimes[whichResponse] = info.rt;
					responseKeys[whichResponse] = info.key;
				}

				if (trial.continue_after_response) {

					if(checkAllResponsesAreValid()){
						end_trial();
					}

				}

			};

			// flattened version of the choices array
			var allchoices = [];
			for(var i=0;i<trial.choices.length; i++){
				allchoices = allchoices.concat(trial.choices[i]);
			}

			var whichStimulus = 0;

			function showNextStimulus(){

				// display stimulus
				if (!trial.is_html) {
					display_element.append($('<img>', {
						src: trial.stimuli[whichStimulus],
						id: 'jspsych-multi-stim-multi-response-stimulus'
					}));
				} else {
					display_element.append($('<div>', {
						html: trial.stimuli[whichStimulus],
						id: 'jspsych-multi-stim-multi-response-stimulus'
					}));
				}

				//show prompt if there is one
				if (trial.prompt !== "") {
					display_element.append(trial.prompt);
				}

				if (typeof trial.timing_stim[whichStimulus] !== 'undefined' && trial.timing_stim[whichStimulus] > 0) {
					var t1 = setTimeout(function() {
						// clear the display, or hide the display
						if(typeof trial.stimuli[whichStimulus + 1] !== 'undefined'){
							display_element.html('');
							// show the next stimulus
							whichStimulus++;
							showNextStimulus();
						} else {
							$('#jspsych-multi-stim-multi-response-stimulus').css('visibility','hidden');
						}

					}, trial.timing_stim[whichStimulus]);

					setTimeoutHandlers.push(t1);
				}

			}

			// show first stimulus
			showNextStimulus();

			// start the response listener
			var keyboardListener = jsPsych.pluginAPI.getKeyboardResponse(after_response, allchoices, "date", true);

			// end trial if time limit is set
			if (trial.timing_response > 0) {
				var t2 = setTimeout(function() {
					end_trial();
				}, trial.timing_response);
				setTimeoutHandlers.push(t2);
			}

		};

		return plugin;
	})();
})(jQuery);