1) example 2) decelerating: callback is called at exponential rate, till max maximum delay is reached. 3) decelerating: callback is called at exponential rate if test satisfies, till max maximum delay is reached.

decelerating-and-callback-with-test-condition.js

// source from https://stackoverflow.com/a/7445863/713573

function decelerating (callback, opts= {}) {
  const {initialDelay = 100, exp = 2, maxDelay = 10000, test} = opts;
  const myFunction = function() {
    console.log('[debug] time: %s, delay: %s', Date.now(), delay);
    if (test()) {
      callback();
      delay *= exp;
      if (delay > maxDelay) {
        delay = initialDelay;
      }
    } else {
      delay = initialDelay;
    }
    setTimeout(myFunction, delay);
  }

  let delay = initialDelay;
  setTimeout(myFunction, delay);
};

// function to test the condition if to start delcaration
function testFunc () {
  return errStarted;
}

let errStarted = false;

decelerating (
  () => console.log('called'),
  {test: testFunc}
);

setTimeout(() => {
  errStarted = true;
}, 2000);

setTimeout(() => {
  errStarted = false;
}, 20000);

decelerating.js

// source from https://stackoverflow.com/a/7445863/713573

function decelerating (callback, opts= {}) {
  const {initialDelay = 10, exp = 2, maxDelay = 10000} = opts;
  const myFunction = function() {
    console.log('[debug] time: %s, delay: %s', Date.now(), delay);
    callback();
    delay *= exp;
    if (delay > maxDelay) {
      delay = initialDelay;
    }
    setTimeout(myFunction, delay);
  }
  
  let delay = initialDelay;
  setTimeout(myFunction, delay);
}

decelerating (() => console.log('called'))

exp-timeout-example.js

// source from https://stackoverflow.com/a/7445863/713573
const initialDelay = 5;
const exp = 2;
const maxDelay = 4000;

const myFunction = function() {
    console.log('time: %s, delay: %s', Date.now(), delay);
    delay *= exp;
    if (delay > maxDelay) {
      delay = initialDelay;
    }   
    setTimeout(myFunction, delay);
}

let delay = initialDelay;
setTimeout(myFunction, delay);