Welcome to Subscribe On Youtube
2725. Interval Cancellation
Description
Given a function fn
, an array of arguments args
, and an interval time t
, return a cancel function cancelFn
.
The function fn
should be called with args
immediately and then called again every t
milliseconds until cancelFn
is called at cancelTimeMs
ms.
Example 1:
Input: fn = (x) => x * 2, args = [4], t = 35 Output: [ {"time": 0, "returned": 8}, {"time": 35, "returned": 8}, {"time": 70, "returned": 8}, {"time": 105, "returned": 8}, {"time": 140, "returned": 8}, {"time": 175, "returned": 8} ] Explanation: const cancelTimeMs = 190; const cancelFn = cancellable((x) => x * 2, [4], 35); setTimeout(cancelFn, cancelTimeMs); Every 35ms, fn(4) is called. Until t=190ms, then it is cancelled. 1st fn call is at 0ms. fn(4) returns 8. 2nd fn call is at 35ms. fn(4) returns 8. 3rd fn call is at 70ms. fn(4) returns 8. 4th fn call is at 105ms. fn(4) returns 8. 5th fn call is at 140ms. fn(4) returns 8. 6th fn call is at 175ms. fn(4) returns 8. Cancelled at 190ms
Example 2:
Input: fn = (x1, x2) => (x1 * x2), args = [2, 5], t = 30 Output: [ {"time": 0, "returned": 10}, {"time": 30, "returned": 10}, {"time": 60, "returned": 10}, {"time": 90, "returned": 10}, {"time": 120, "returned": 10}, {"time": 150, "returned": 10} ] Explanation: const cancelTimeMs = 165; const cancelFn = cancellable((x1, x2) => (x1 * x2), [2, 5], 30) setTimeout(cancelFn, cancelTimeMs) Every 30ms, fn(2, 5) is called. Until t=165ms, then it is cancelled. 1st fn call is at 0ms 2nd fn call is at 30ms 3rd fn call is at 60ms 4th fn call is at 90ms 5th fn call is at 120ms 6th fn call is at 150ms Cancelled at 165ms
Example 3:
Input: fn = (x1, x2, x3) => (x1 + x2 + x3), args = [5, 1, 3], t = 50 Output: [ {"time": 0, "returned": 9}, {"time": 50, "returned": 9}, {"time": 100, "returned": 9}, {"time": 150, "returned": 9} ] Explanation: const cancelTimeMs = 180; const cancelFn = cancellable((x1, x2, x3) => (x1 + x2 + x3), [5, 1, 3], 50) setTimeout(cancelFn, cancelTimeMs) Every 50ms, fn(5, 1, 3) is called. Until t=180ms, then it is cancelled. 1st fn call is at 0ms 2nd fn call is at 50ms 3rd fn call is at 100ms 4th fn call is at 150ms Cancelled at 180ms
Constraints:
fn
is a functionargs
is a valid JSON array1 <= args.length <= 10
30 <= t <= 100
10 <= cancelTimeMs <= 500
Solutions

function cancellable(fn: Function, args: any[], t: number): Function { fn(...args); const time = setInterval(() => fn(...args), t); return () => clearInterval(time); } /** * const result = [] * * const fn = (x) => x * 2 * const args = [4], t = 20, cancelT = 110 * * const log = (...argsArr) => { * result.push(fn(...argsArr)) * } * * const cancel = cancellable(fn, args, t); * * setTimeout(() => { * cancel() * console.log(result) // [ * // {"time":0,"returned":8}, * // {"time":20,"returned":8}, * // {"time":40,"returned":8}, * // {"time":60,"returned":8}, * // {"time":80,"returned":8}, * // {"time":100,"returned":8} * // ] * }, cancelT) */