draft of button response plugin

plugins/jspsych-button-response.js

@@ -0,0 +1,158 @@
+/**
+ * jspsych-button-response
+ * Josh de Leeuw
+ *
+ * plugin for displaying a stimulus and getting a keyboard response
+ *
+ * documentation: docs.jspsych.org
+ *
+ **/
+
+(function($) {
+	jsPsych["button-response"] = (function() {
+
+		var plugin = {};
+
+		plugin.create = function(params) {
+
+			params = jsPsych.pluginAPI.enforceArray(params, ['stimuli', 'choices']);
+
+			var trials = new Array(params.stimuli.length);
+			for (var i = 0; i < trials.length; i++) {
+				trials[i] = {};
+				trials[i].a_path = params.stimuli[i];
+				trials[i].choices = params.choices;
+				trials[i].button_html = params.button_html || '<button>%choice%</button>';
+				trials[i].response_ends_trial = (typeof params.response_ends_trial === 'undefined') ? true : params.response_ends_trial;
+				// timing parameters
+				trials[i].timing_stim = params.timing_stim || -1; // if -1, then show indefinitely
+				trials[i].timing_response = params.timing_response || -1; // if -1, then wait for response forever
+				// optional parameters
+				trials[i].is_html = (typeof params.is_html === 'undefined') ? false : params.is_html;
+				trials[i].prompt = (typeof params.prompt === 'undefined') ? "" : params.prompt;
+			}
+			return trials;
+		};
+
+
+
+		plugin.trial = function(display_element, trial) {
+
+			// if any trial variables are functions
+			// this evaluates the function and replaces
+			// it with the output of the function
+			trial = jsPsych.pluginAPI.evaluateFunctionParameters(trial);
+
+			// this array holds handlers from setTimeout calls
+			// that need to be cleared if the trial ends early
+			var setTimeoutHandlers = [];
+
+			// display stimulus
+			if (!trial.is_html) {
+				display_element.append($('<img>', {
+					src: trial.a_path,
+					id: 'jspsych-button-response-stimulus'
+				}));
+			} else {
+				display_element.append($('<div>', {
+					html: trial.a_path,
+					id: 'jspsych-button-response-stimulus'
+				}));
+			}
+
+			//display buttons
+			var buttons = [];
+			if(Array.isArray(trial.button_html)){
+				if(trial.button_html.length == trial.choices.length){
+					buttons = trial.button_html;
+				} else {
+					console.error('Error in button-response plugin. The length of the button_html array does not equal the length of the choices array');
+				}
+			} else {
+				for(var i=0;i < trial.choices.length; i++){
+					buttons.push(trial.button_html);
+				}
+			}
+			for(var i=0; i<trial.choices.length; i++){
+				var str = trial.button_html[i].replace('%choice%', trial.choice[i]);
+				display_element.append($(str, {
+					id: 'jspsych-button-response-button-'+i,
+					class: 'jspsych-button-response-button'
+				}));
+			}
+
+			//show prompt if there is one
+			if (trial.prompt !== "") {
+				display_element.append(trial.prompt);
+			}
+
+			// store response
+			var response = {rt: -1, button: -1};
+
+			// 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
+				if(typeof keyboardListener !== 'undefined'){
+					jsPsych.pluginAPI.cancelKeyboardResponse(keyboardListener);
+				}
+
+				// gather the data to store for the trial
+				var trial_data = {
+					"rt": response.rt,
+					"stimulus": trial.a_path,
+					"key_press": response.key
+				};
+
+				jsPsych.data.write(trial_data);
+
+				// clear the display
+				display_element.html('');
+
+				// move on to the next trial
+				jsPsych.finishTrial();
+			};
+
+			// function to handle responses by the subject
+			var after_response = function(info) {
+
+				// after a valid response, the stimulus will have the CSS class 'responded'
+				// which can be used to provide visual feedback that a response was recorded
+				$("#jspsych-button-response-stimulus").addClass('responded');
+
+				// only record the first response
+				if(response.button == -1){
+					response = info;
+				}
+
+				if (trial.response_ends_trial) {
+					end_trial();
+				}
+			};
+
+			// hide image if timing is set
+			if (trial.timing_stim > 0) {
+				var t1 = setTimeout(function() {
+					$('#jspsych-button-response-stimulus').css('visibility', 'hidden');
+				}, trial.timing_stim);
+				setTimeoutHandlers.push(t1);
+			}
+
+			// 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);