Topic Description

Imagine you are developing a project that tracks different metrics. We need a counter function, but it is more complex than a regular counter. Please design a function named createCounter that optionally accepts an initial value as a parameter. This function should return a new function.

When you call this new function for the first time, it should return the initial value if provided, or the default value of 0 if not. Interestingly, each subsequent call should return a value that is incremented by 1 from the previous return value. Note that we want this behavior encapsulated within this function.

// No initial value provided
const counter = createCounter();
counter(); // 0
counter(); // 1
counter(); // 2

// Initial value provided is 10
const counter = createCounter(10);
counter(); // 10
counter(); // 11
counter(); // 12

Answer

function createCounter(initNum = 0){
	let sum = initNum - 1
	return function(){
		sum+=1
		return sum
	}
}

function createCounter(initialValue = 0) {
  let count = initialValue;

  return () => {
    return count++;
  };
}