Add validation for func and wait

Author: pertrai1

greatfrontend/gfe-75/README.md

@@ -10,7 +10,7 @@ The GFE 75 is GreatFrontEnd's curated collection of 75 essential frontend coding
 
 | Category             | Completed | Total | Percentage |
 | -------------------- | --------- | ----- | ---------- |
-| JavaScript Utilities | 3         | 30    | 10%        |
+| JavaScript Utilities | 3         | 20    | 10%        |
 | DOM Manipulation     | 0         | 15    | 0%         |
 | Async Programming    | 0         | 12    | 0%         |
 | Components           | 0         | 10    | 0%         |
@@ -23,6 +23,7 @@ The GFE 75 is GreatFrontEnd's curated collection of 75 essential frontend coding
 
 - [Debounce](./javascript-utilities/debounce/) - Medium
 - [Flatten](./javascript-utilities/flatten/) - Medium
+- [Throttle](./javascript-utilities/throttle/) - Medium
 
 ### DOM Manipulation (0/15)
 

greatfrontend/gfe-75/javascript-utilities/throttle/throttle.ts

@@ -1,11 +1,32 @@
+/**
+ * Throttle a function so that it can only be called once per wait period.
+ * @time O(1) for each call
+ * @space O(1) for the closure variables
+ */
+
 /* eslint-disable @typescript-eslint/no-explicit-any */
 type ThrottleFn<T extends any[]> = (...args: T) => any;
 
+function validateFunc<T extends any[]>(fn: ThrottleFn<T>): void {
+  if (typeof fn !== 'function') {
+    throw new TypeError('First argument must be a function');
+  }
+}
+
+function validateWait(wait: number): void {
+  if (typeof wait !== 'number' || wait < 0 || !Number.isFinite(wait)) {
+    throw new TypeError('Wait must be a non-negative finite number');
+  }
+}
+
 // Leading edge with timestamp
-export default function throttle<T extends any[]>(
+export function throttle<T extends any[]>(
   func: ThrottleFn<T>,
   wait: number
 ): ThrottleFn<T> {
+  validateFunc(func);
+  validateWait(wait);
+
   let lastCallTime = 0;
 
   return function (this: any, ...args: T) {
@@ -22,6 +43,9 @@ export function throttleTrailingEdge<T extends any[]>(
   func: ThrottleFn<T>,
   wait: number
 ): ThrottleFn<T> {
+  validateFunc(func);
+  validateWait(wait);
+
   let timeoutId: ReturnType<typeof setTimeout> | null = null;
   let lastArgs: T | undefined;