index.ts

import { JsPsych, JsPsychPlugin, ParameterType, TrialType } from "jspsych";

import { version } from "../package.json";

const info = <const>{
  name: "html-slider-response",
  version: version,
  parameters: {
    /** The HTML string to be displayed */
    stimulus: {
      type: ParameterType.HTML_STRING,
      default: undefined,
    },
    /** Sets the minimum value of the slider. */
    min: {
      type: ParameterType.INT,
      default: 0,
    },
    /** Sets the maximum value of the slider */
    max: {
      type: ParameterType.INT,
      default: 100,
    },
    /** Sets the starting value of the slider */
    slider_start: {
      type: ParameterType.INT,
      default: 50,
    },
    /** Sets the step of the slider. This is the smallest amount by which the slider can change. */
    step: {
      type: ParameterType.INT,
      default: 1,
    },
    /** Labels displayed at equidistant locations on the slider. For example, two labels will be placed at the ends of the slider. Three labels would place two at the ends and one in the middle. Four will place two at the ends, and the other two will be at 33% and 67% of the slider width. */
    labels: {
      type: ParameterType.HTML_STRING,
      default: [],
      array: true,
    },
    /** Set the width of the slider in pixels. If left null, then the width will be equal to the widest element in the display. */
    slider_width: {
      type: ParameterType.INT,
      default: null,
    },
    /** Label of the button to end the trial. */
    button_label: {
      type: ParameterType.STRING,
      default: "Continue",
      array: false,
    },
    /** If true, the participant must move the slider before clicking the continue button. */
    require_movement: {
      type: ParameterType.BOOL,
      default: false,
    },
    /** This string can contain HTML markup. Any content here will be displayed below the stimulus. The intention is that it can be used to provide a reminder about the action the participant is supposed to take (e.g., which key to press). */
    prompt: {
      type: ParameterType.HTML_STRING,
      default: null,
    },
    /** How long to display the stimulus in milliseconds. The visibility CSS property of the stimulus will be set to `hidden` after this time has elapsed. If this is null, then the stimulus will remain visible until the trial ends. */
    stimulus_duration: {
      type: ParameterType.INT,
      default: null,
    },
    /** How long to wait for the participant to make a response before ending the trial in milliseconds. If the participant fails to make a response before this timer is reached, the participant's response will be recorded as null for the trial and the trial will end. If the value of this parameter is null, then the trial will wait for a response indefinitely. */
    trial_duration: {
      type: ParameterType.INT,
      default: null,
    },
    /** If true, then the trial will end whenever the participant makes a response (assuming they make their response before the cutoff specified by the `trial_duration` parameter). If false, then the trial will continue until the value for `trial_duration` is reached. You can set this parameter to `false` to force the participant to view a stimulus for a fixed amount of time, even if they respond before the time is complete. */
    response_ends_trial: {
      type: ParameterType.BOOL,
      default: true,
    },
    /** If true, the slider's value will be displayed in real time below the slider. */
    value_display: {
      type: ParameterType.BOOL,
      default: false,
  },

  },
  data: {
    /** The time in milliseconds for the participant to make a response. The time is measured from when the stimulus first appears on the screen until the participant's response. */
    rt: {
      type: ParameterType.INT,
    },
    /** The numeric value of the slider. */
    response: {
      type: ParameterType.INT,
    },
    /** The HTML content that was displayed on the screen. */
    stimulus: {
      type: ParameterType.HTML_STRING,
    },
    /** The starting value of the slider. */
    slider_start: {
      type: ParameterType.INT,
    },
  },
};

type Info = typeof info;

/**
 * This plugin displays HTML content and allows the participant to respond by dragging a slider.
 * @author Josh de Leeuw
 * @see {@link https://www.jspsych.org/latest/plugins/html-slider-response/ html-slider-response plugin documentation on jspsych.org}
 */
class HtmlSliderResponsePlugin implements JsPsychPlugin<Info> {
  static info = info;

  constructor(private jsPsych: JsPsych) {}

  trial(display_element: HTMLElement, trial: TrialType<Info>) {
    // half of the thumb width value from jspsych.css, used to adjust the label positions
    var half_thumb_width = 7.5;

    var html = '<div id="jspsych-html-slider-response-wrapper" style="margin: 100px 0px;">';
    html += '<div id="jspsych-html-slider-response-stimulus">' + trial.stimulus + "</div>";
    html +=
      '<div class="jspsych-html-slider-response-container" style="position:relative; margin: 0 auto 3em auto; ';
    if (trial.slider_width !== null) {
      html += "width:" + trial.slider_width + "px;";
    } else {
      html += "width:auto;";
    }
    html += '">';
    html +=
      '<input type="range" class="jspsych-slider" value="' +
      trial.slider_start +
      '" min="' +
      trial.min +
      '" max="' +
      trial.max +
      '" step="' +
      trial.step +
      '" id="jspsych-html-slider-response-response" ';
    if (trial.value_display) {
        html += 'oninput="this.nextElementSibling.value = this.value"></input>';
        html += "<output>" + trial.slider_start + "</output>";
    }else{
        html += "></input>";
    }
    html += "<div>";
    for (var j = 0; j < trial.labels.length; j++) {
      var label_width_perc = 100 / (trial.labels.length - 1);
      var percent_of_range = j * (100 / (trial.labels.length - 1));
      var percent_dist_from_center = ((percent_of_range - 50) / 50) * 100;
      var offset = (percent_dist_from_center * half_thumb_width) / 100;
      html +=
        '<div style="border: 1px solid transparent; display: inline-block; position: absolute; ' +
        "left:calc(" +
        percent_of_range +
        "% - (" +
        label_width_perc +
        "% / 2) - " +
        offset +
        "px); text-align: center; width: " +
        label_width_perc +
        '%;">';
      html += '<span style="text-align: center; font-size: 80%;">' + trial.labels[j] + "</span>";
      html += "</div>";
    }
    html += "</div>";
    html += "</div>";
    html += "</div>";

    if (trial.prompt !== null) {
      html += trial.prompt;
    }

    // add submit button
    html +=
      '<button id="jspsych-html-slider-response-next" class="jspsych-btn" ' +
      (trial.require_movement ? "disabled" : "") +
      ">" +
      trial.button_label +
      "</button>";

    display_element.innerHTML = html;

    var response = {
      rt: null,
      response: null,
    };

    if (trial.require_movement) {
      const enable_button = () => {
        display_element.querySelector<HTMLInputElement>(
          "#jspsych-html-slider-response-next"
        ).disabled = false;
      };

      display_element
        .querySelector("#jspsych-html-slider-response-response")
        .addEventListener("mousedown", enable_button);

      display_element
        .querySelector("#jspsych-html-slider-response-response")
        .addEventListener("touchstart", enable_button);

      display_element
        .querySelector("#jspsych-html-slider-response-response")
        .addEventListener("change", enable_button);
    }

    const end_trial = () => {
      // save data
      var trialdata = {
        rt: response.rt,
        stimulus: trial.stimulus,
        slider_start: trial.slider_start,
        response: response.response,
      };

      // next trial
      this.jsPsych.finishTrial(trialdata);
    };

    display_element
      .querySelector("#jspsych-html-slider-response-next")
      .addEventListener("click", () => {
        // measure response time
        var endTime = performance.now();
        response.rt = Math.round(endTime - startTime);
        response.response = display_element.querySelector<HTMLInputElement>(
          "#jspsych-html-slider-response-response"
        ).valueAsNumber;

        if (trial.response_ends_trial) {
          end_trial();
        } else {
          display_element.querySelector<HTMLButtonElement>(
            "#jspsych-html-slider-response-next"
          ).disabled = true;
        }
      });

    if (trial.stimulus_duration !== null) {
      this.jsPsych.pluginAPI.setTimeout(() => {
        display_element.querySelector<HTMLElement>(
          "#jspsych-html-slider-response-stimulus"
        ).style.visibility = "hidden";
      }, trial.stimulus_duration);
    }

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

    var startTime = performance.now();
  }

  simulate(
    trial: TrialType<Info>,
    simulation_mode,
    simulation_options: any,
    load_callback: () => void
  ) {
    if (simulation_mode == "data-only") {
      load_callback();
      this.simulate_data_only(trial, simulation_options);
    }
    if (simulation_mode == "visual") {
      this.simulate_visual(trial, simulation_options, load_callback);
    }
  }

  private create_simulation_data(trial: TrialType<Info>, simulation_options) {
    const default_data = {
      stimulus: trial.stimulus,
      slider_start: trial.slider_start,
      response: this.jsPsych.randomization.randomInt(trial.min, trial.max),
      rt: this.jsPsych.randomization.sampleExGaussian(500, 50, 1 / 150, true),
    };

    const data = this.jsPsych.pluginAPI.mergeSimulationData(default_data, simulation_options);

    this.jsPsych.pluginAPI.ensureSimulationDataConsistency(trial, data);

    return data;
  }

  private simulate_data_only(trial: TrialType<Info>, simulation_options) {
    const data = this.create_simulation_data(trial, simulation_options);

    this.jsPsych.finishTrial(data);
  }

  private simulate_visual(trial: TrialType<Info>, simulation_options, load_callback: () => void) {
    const data = this.create_simulation_data(trial, simulation_options);

    const display_element = this.jsPsych.getDisplayElement();

    this.trial(display_element, trial);
    load_callback();

    if (data.rt !== null) {
      const el = display_element.querySelector<HTMLInputElement>("input[type='range']");

      setTimeout(() => {
        this.jsPsych.pluginAPI.clickTarget(el);
        el.valueAsNumber = data.response;
      }, data.rt / 2);

      this.jsPsych.pluginAPI.clickTarget(display_element.querySelector("button"), data.rt);
    }
  }
}

export default HtmlSliderResponsePlugin;