Question

2805. Custom Interval

中文文档

Description

Function customInterval

Given a function fn, a number delay and a number period, return a number id. customInterval is a function that should execute the provided function fn at intervals based on a linear pattern defined by the formula delay + period * count. The count in the formula represents the number of times the interval has been executed starting from an initial value of 0.

Function customClearInterval 

Given the id. id is the returned value from the function customInterval. customClearInterval should stop executing provided function fn at intervals.

Note: The setTimeout and setInterval functions in Node.js return an object, not a number.

 

Example 1:

Input: delay = 50, period = 20, cancelTime = 225
Output: [50,120,210]
Explanation: 
const t = performance.now()  
const result = []
        
const fn = () => {
  result.push(Math.floor(performance.now() - t))
}
const id = customInterval(fn, delay, period)

setTimeout(() => {
  customClearInterval(id)
}, 225)

50 + 20 * 0 = 50 // 50ms - 1st function call
50 + 20 * 1 = 70 // 50ms + 70ms = 120ms - 2nd function call
50 + 20 * 2 = 90 // 50ms + 70ms + 90ms = 210ms - 3rd function call

Example 2:

Input: delay = 20, period = 20, cancelTime = 150
Output: [20,60,120]
Explanation: 
20 + 20 * 0 = 20 // 20ms - 1st function call
20 + 20 * 1 = 40 // 20ms + 40ms = 60ms - 2nd function call
20 + 20 * 2 = 60 // 20ms + 40ms + 60ms = 120ms - 3rd function call

Example 3:

Input: delay = 100, period = 200, cancelTime = 500
Output: [100,400]
Explanation: 
100 + 200 * 0 = 100 // 100ms - 1st function call
100 + 200 * 1 = 300 // 100ms + 300ms = 400ms - 2nd function call

 

Constraints:

• 20 <= delay, period <= 250
• 20 <= cancelTime <= 1000

Solutions

Solution 1

const intervalMap = new Map<number, NodeJS.Timeout>();

function customInterval(fn: Function, delay: number, period: number): number {
  let count = 0;
  function recursiveTimeout() {
    intervalMap.set(
      id,
      setTimeout(() => {
        fn();
        count++;
        recursiveTimeout();
      }, delay + period * count),
    );
  }

  const id = Date.now();
  recursiveTimeout();
  return id;
}

function customClearInterval(id: number) {
  if (intervalMap.has(id)) {
    clearTimeout(intervalMap.get(id)!);
    intervalMap.delete(id);
  }
}