2627-debounce

2627. Debounce (Medium) (https://leetcode.com/problems/debounce/)

Given a function fn and a time in milliseconds t, return a debounced version of that function. A debounced function is a function whose execution is delayed by t milliseconds and whose execution is cancelled if it is called again within that window of time. The debounced function should also receive the passed parameters. For example, if t = 50ms and the function was called at 30ms, 60ms, and 100ms, the first 2 function calls would be cancelled, and the 3rd function call would be executed at 150ms. Please solve it without using lodash’s _.debounce() function. Constraints: - 0 <= t <= 1000 - 1 <= calls.length <= 10 - 0 <= calls[i].t <= 1000 - 0 <= calls[i].inputs.length <= 10

type F = (...args: number[]) => void
 
function debounce(fn: F, t: number): F {
  let timer: ReturnType<typeof setTimeout>
 
  return function (...args) {
    clearTimeout(timer)
 
    timer = setTimeout(() => {
      fn(...args)
    }, t)
  }
}
 
const log = debounce(console.log, 100)
log('Hello') // cancelled
console.log('1')
log('Hello') // cancelled
console.log('2')
log('Hello') // Logged at t=100ms

Example 1:
 
    Input:
    t = 50
    calls = [
      { "t": 50, inputs: [1] },
      { "t": 75, inputs: [2] }
    ]
    Output: [{ "t": 125, inputs: [2] }]
    Explanation:
    The 1st call is cancelled by the 2nd call because the 2nd call occurred
    before 100ms. The 2nd call is delayed by 50ms and executed at 125ms.
    The inputs were (2).
 
  Example 2:
 
    Input:
    t = 20
    calls = [
      { "t": 50, inputs: [1] },
      { "t": 100, inputs: [2] }
    ]
    Output: [{ "t": 70, inputs: [1] }, { "t": 120, inputs: [2] }]
    Explanation:
    The 1st call is delayed until 70ms. The inputs were (1).
    The 2nd call is delayed until 120ms. The inputs were (2).
 
  Example 3:
 
<!-- [[leetcode/untagged]] [[leetcode/untagged/2626-array-reduce-transformation]] [[leetcode/untagged/2629-function-composition]] -->
 
    Input:
    t = 150
    calls = [
      { "t": 50, inputs: [1, 2] },
      { "t": 300, inputs: [3, 4] },
      { "t": 300, inputs: [5, 6] }
    ]
    Output: [{ "t": 200, inputs: [1, 2] }, { "t": 450, inputs: [5, 6] }]
    Explanation:
    The 1st call is delayed by 150ms and ran at 200ms. The inputs were (1, 2).
    The 2nd call is cancelled by the 3rd call.
    The 3rd call is delayed by 150ms and ran at 450ms. The inputs were (5, 6).