jspsych-plugins/plugins/jspsych-html-keyboard-response-clickable.js

/**
 * jspsych-html-keyboard-response-clickable
 * Etienne Gaudrain
 *
 * Based on:
 * jspsych-html-keyboard-response @6.1.0
 * Josh de Leeuw
 *
 * Like html-keyboard-response, but where clicking elements with class "clickable" will end the trial.
 *
 **/


jsPsych.plugins["html-keyboard-response-clickable"] = (function() {

    var plugin = {};

    plugin.info = {
        name: 'html-keyboard-response-clickable',
        description: 'Like html-keyboard-response, but where clicking elements with class "clickable" will end the trial.',
        parameters: {
            stimulus: {
                type: jsPsych.plugins.parameterType.HTML_STRING,
                pretty_name: 'Stimulus',
                default: undefined,
                description: 'The HTML string to be displayed'
            },
            choices: {
                type: jsPsych.plugins.parameterType.KEYCODE,
                array: true,
                pretty_name: 'Choices',
                default: jsPsych.ALL_KEYS,
                description: 'The keys the subject is allowed to press to respond to the stimulus.'
            },
            clickable: {
                type: jsPsych.plugins.parameterType.BOOL,
                pretty_name: 'Clickable',
                description: 'Clicking clickable elements ends trial.',
                default: true
            },
            prompt: {
                type: jsPsych.plugins.parameterType.STRING,
                pretty_name: 'Prompt',
                default: null,
                description: 'Any content here will be displayed below the stimulus.'
            },
            stimulus_duration: {
                type: jsPsych.plugins.parameterType.INT,
                pretty_name: 'Stimulus duration',
                default: null,
                description: 'How long to hide the stimulus.'
            },
            trial_duration: {
                type: jsPsych.plugins.parameterType.INT,
                pretty_name: 'Trial duration',
                default: null,
                description: 'How long to show trial before it ends.'
            },
            response_ends_trial: {
                type: jsPsych.plugins.parameterType.BOOL,
                pretty_name: 'Response ends trial',
                default: true,
                description: 'If true, trial will end when subject makes a response.'
            },

        }
    }

    plugin.trial = function(display_element, trial) {

        var start_time;
        var new_html = '<div id="jspsych-html-keyboard-response-stimulus">' + trial.stimulus + '</div>';

        // add prompt
        if(trial.prompt !== null) {
            new_html += trial.prompt;
        }

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

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

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

            // 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.stimulus,
                "key_press": response.key
            };

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

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

        // 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
            display_element.querySelector('#jspsych-html-keyboard-response-stimulus').className += ' responded';

            // only record the first response
            if(response.key == null) {
                response = info;
            }

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

        // draw
        display_element.innerHTML = new_html;
        start_time = performance.now();

        if(trial.clickable){
            display_element.querySelectorAll(".clickable").forEach(function(e){
                var clickHandler = function(event){
                    event.preventDefault();
                    var info = {'key': 'clicked', 'rt': performance.now()-start_time};
                    after_response(info);
                    e.removeEventListener('click', clickHandler);
                };
                e.addEventListener('click', clickHandler);
            });
        }

        // start the response listener
        if(trial.choices != jsPsych.NO_KEYS) {
            var keyboardListener = jsPsych.pluginAPI.getKeyboardResponse({
                callback_function: after_response,
                valid_responses: trial.choices,
                rt_method: 'performance',
                persist: false,
                allow_held_key: false
            });
        }

        // hide stimulus if stimulus_duration is set
        if(trial.stimulus_duration !== null) {
            jsPsych.pluginAPI.setTimeout(function() {
                display_element.querySelector('#jspsych-html-keyboard-response-stimulus').style.visibility = 'hidden';
            }, trial.stimulus_duration);
        }

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

    };

    return plugin;
})();