<p>Given a function <code>fn</code>, an array of arguments <code>args</code>, and a timeout <code>t</code> in milliseconds, return a cancel function <code>cancelFn</code>.</p> <p>After a delay of <code>cancelTimeMs</code>, the returned cancel function <code>cancelFn</code> will be invoked.</p> <pre> setTimeout(cancelFn, cancelTimeMs) </pre> <p>Initially, the execution of the function <code>fn</code> should be delayed by <code>t</code> milliseconds.</p> <p>If, before the delay of <code>t</code> milliseconds, the function <code>cancelFn</code> is invoked, it should cancel the delayed execution of <code>fn</code>. Otherwise, if <code>cancelFn</code> is not invoked within the specified delay <code>t</code>, <code>fn</code> should be executed with the provided <code>args</code> as arguments.</p> <p> </p> <p><strong class="example">Example 1:</strong></p> <pre> <strong>Input:</strong> fn = (x) => x * 5, args = [2], t = 20 <strong>Output:</strong> [{"time": 20, "returned": 10}] <strong>Explanation:</strong> const cancelTimeMs = 50; const result = []; const fn = (x) => x * 5; const start = performance.now(); const log = (...argsArr) => { const diff = Math.floor(performance.now() - start); result.push({"time": diff, "returned": fn(...argsArr)}); } const cancel = cancellable(log, [2], 20); const maxT = Math.max(t, 50); setTimeout(cancel, cancelTimeMs); setTimeout(() => { console.log(result); // [{"time":20,"returned":10}] }, maxT + 15); The cancellation was scheduled to occur after a delay of cancelTimeMs (50ms), which happened after the execution of fn(2) at 20ms. </pre> <p><strong class="example">Example 2:</strong></p> <pre> <strong>Input:</strong> fn = (x) => x**2, args = [2], t = 100 <strong>Output:</strong> [] <strong>Explanation:</strong> const cancelTimeMs = 50; The cancellation was scheduled to occur after a delay of cancelTimeMs (50ms), which happened before the execution of fn(2) at 100ms, resulting in fn(2) never being called. </pre> <p><strong class="example">Example 3:</strong></p> <pre> <strong>Input:</strong> fn = (x1, x2) => x1 * x2, args = [2,4], t = 30 <strong>Output:</strong> [{"time": 30, "returned": 8}] <strong>Explanation: </strong>const cancelTimeMs = 100; The cancellation was scheduled to occur after a delay of cancelTimeMs (100ms), which happened after the execution of fn(2,4) at 30ms. </pre> <p> </p> <p><strong>Constraints:</strong></p> <ul> <li><code>fn</code> is a function</li> <li><code>args</code> is a valid JSON array</li> <li><code>1 <= args.length <= 10</code></li> <li><code><font face="monospace">20 <= t <= 1000</font></code></li> <li><code><font face="monospace">10 <= cancelTimeMs <= 1000</font></code></li> </ul>