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75 lines
2.9 KiB
HTML
75 lines
2.9 KiB
HTML
<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>
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<p>After a delay of <code>cancelTimeMs</code>, the returned cancel function <code>cancelFn</code> will be invoked.</p>
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<pre>
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setTimeout(cancelFn, cancelTimeMs)
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</pre>
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<p>Initially, the execution of the function <code>fn</code> should be delayed by <code>t</code> milliseconds.</p>
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<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>
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<p> </p>
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<p><strong class="example">Example 1:</strong></p>
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<pre>
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<strong>Input:</strong> fn = (x) => x * 5, args = [2], t = 20
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<strong>Output:</strong> [{"time": 20, "returned": 10}]
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<strong>Explanation:</strong>
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const cancelTimeMs = 50;
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const result = [];
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const fn = (x) => x * 5;
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const start = performance.now();
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const log = (...argsArr) => {
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const diff = Math.floor(performance.now() - start);
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result.push({"time": diff, "returned": fn(...argsArr)});
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}
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const cancel = cancellable(log, [2], 20);
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const maxT = Math.max(t, 50);
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setTimeout(cancel, cancelTimeMs);
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setTimeout(() => {
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console.log(result); // [{"time":20,"returned":10}]
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}, maxT + 15);
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The cancellation was scheduled to occur after a delay of cancelTimeMs (50ms), which happened after the execution of fn(2) at 20ms.
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</pre>
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<p><strong class="example">Example 2:</strong></p>
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<pre>
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<strong>Input:</strong> fn = (x) => x**2, args = [2], t = 100
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<strong>Output:</strong> []
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<strong>Explanation:</strong>
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const cancelTimeMs = 50;
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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.
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</pre>
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<p><strong class="example">Example 3:</strong></p>
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<pre>
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<strong>Input:</strong> fn = (x1, x2) => x1 * x2, args = [2,4], t = 30
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<strong>Output:</strong> [{"time": 30, "returned": 8}]
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<strong>Explanation:
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</strong>const cancelTimeMs = 100;
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The cancellation was scheduled to occur after a delay of cancelTimeMs (100ms), which happened after the execution of fn(2,4) at 30ms.
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</pre>
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<p> </p>
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<p><strong>Constraints:</strong></p>
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<ul>
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<li><code>fn</code> is a function</li>
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<li><code>args</code> is a valid JSON array</li>
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<li><code>1 <= args.length <= 10</code></li>
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<li><code><font face="monospace">20 <= t <= 1000</font></code></li>
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<li><code><font face="monospace">10 <= cancelTimeMs <= 1000</font></code></li>
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</ul>
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