interval cancellation javascript program

Author: jeffersonbalde

IntervalCancellation.js

@@ -0,0 +1,50 @@
+// 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 cancelT ms.
+
+/**
+ * @param {Function} fn
+ * @param {Array} args
+ * @param {number} t
+ * @return {Function}
+ */
+var cancellable = function(fn, args, t) {
+    fn(...args);
+    let timer = setInterval(() => fn(...args), t);
+
+    let cancelFn = () => clearInterval(timer);
+    return cancelFn;
+};
+
+/**
+ *  const result = []
+ *
+ *  const fn = (x) => x * 2
+ *  const args = [4], t = 35, cancelT = 190
+ *
+ *  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, args, t);
+ *
+ *  setTimeout(() => {
+ *     cancel()
+ *  }, cancelT)
+ *   
+ *  setTimeout(() => {
+ *    console.log(result)  // [
+ *                         //      {"time":0,"returned":8},
+ *                         //      {"time":35,"returned":8},
+ *                         //      {"time":70,"returned":8},           
+ *                         //      {"time":105,"returned":8},
+ *                         //      {"time":140,"returned":8},
+ *                         //      {"time":175,"returned":8}
+ *                         //  ]
+ *  }, cancelT + t + 15)    
+ */