init commit

shared/components/src/utils/throttle.ts

@@ -0,0 +1,49 @@
+/* eslint-disable import/prefer-default-export */
+/**
+ * @name throttle
+ * @description
+ * Creates a throttled function that only invokes func at most once per every limit time (ms).
+ *
+ * *NOTE: this does not capture or recall all functions that were triggered.
+ * This will drop function calls that happen during the throttle time*
+ * @param limit - time to wait between calls in ms
+ * @example
+ * Normal event
+ * event      | |   |   |
+ * time     ----------------
+ * callback   | |   |   |
+ *
+ * Throttled event [300ms]
+ * event    |   |   |    |
+ * time     ----------------
+ * callback |      |      |
+ *             [300]  [300]
+ */
+
+export function throttle<T extends []>(
+    func: (..._: T) => unknown,
+    limit: number,
+): (..._: T) => void {
+    let lastTimeoutId;
+    let lastCallTime: number;
+
+    return function throttled(...args) {
+        const nextCall = () => {
+            func.apply(this, args);
+            lastCallTime = Date.now();
+        };
+
+        if (!lastCallTime) {
+            nextCall();
+        } else {
+            clearTimeout(lastTimeoutId);
+            const timeBetweenCalls = Date.now() - lastCallTime;
+            const waitTime = Math.max(0, limit - timeBetweenCalls);
+            lastTimeoutId = setTimeout(() => {
+                if (timeBetweenCalls >= limit) {
+                    nextCall();
+                }
+            }, waitTime);
+        }
+    };
+}