@jspsych-contrib/extension-countdown

jsPsych Countdown Extension

This extension adds a countdown during a trial.

Parameters

Initialization Parameters

None

Trial Parameters

Trial parameters can be set when adding the extension to a trial object.

let trial = {
  type: jsPsych...,
  extensions: [
    {type: jsPsychExtensionWebgazer, params: {...}}
  ]
}

Parameter	Type	Default Value	Description
time	number	undefined	Time in milliseconds of the countdown
update_time	number	50	How often to update the countdown display; in milliseconds
format	function	(time) => String(Math.floor(time / 1000))	The displayed content of the countdown. Receives the current time left in milliseconds and returns a string for display.

Data Generated

None

Functions

These functions below are provided to enable a better interaction with the countdown. Note that all of the functions below must be prefixed with jsPsych.extensions.countdown (e.g. jsPsych.extensions.countdown.pause()).

pause()

Pauses the countdown.

resume()

Resumes the countdown.

get_time_left()

Gets how much time there is still left in milliseconds.

Example

let jsPsych = initJsPsych({
  extensions: [{ type: jsPsychExtensionCountdown }],
});

let trial = {
  type: jsPsychHtmlKeyboardResponse,
  stimulus: "Hello world",
  extensions: [
    {
      type: jsPsychExtensionCountdown,
      params: {
        time: 5000,
        update_time: 20,
        format: (time) => {
          if (time < 3000) {
            document.querySelector(".jspsych-extension-countdown").style.color = "red";
          }

          let time_in_seconds = time / 1000;

          let minutes = Math.floor(time_in_seconds / 60);
          time_in_seconds -= minutes * 60;

          let seconds = Math.floor(time_in_seconds);

          let format_number = (number) => {
            let temp_str = `0${number}`;
            return temp_str.substring(temp_str.length - 2);
          };

          return `${format_number(minutes)}:${format_number(seconds)}`;
        },
      },
    },
  ],
  on_load: function () {
    setTimeout(() => {
      jsPsych.extensions.countdown.pause();
      setTimeout(() => {
        jsPsych.extensions.countdown.resume();
      }, 2000);
    }, 1000);
  },
};

jsPsych.run([trial]);