🧑‍💻(frontend) Add assert utility for type safety and cleaner checks

Introduces an `assert` utility function.
This function provides a clean way to throw an error
for falsy values, improving code readability and
helping with TypeScript type narrowing
by ensuring a variable's expected state
before proceeding.

Signed-off-by: Robin Weber <[email protected]>

Author: rvveber

src/frontend/apps/impress/src/utils/system.ts

@@ -1,2 +1,20 @@
+/**
+ * @param ms - The number of milliseconds to wait.
+ * @description A utility function that returns a promise that resolves after a specified number of milliseconds.
+ */
 export const sleep = (ms: number) =>
   new Promise((resolve) => setTimeout(resolve, ms));
+
+/**
+ * @param condition - The condition to check.
+ * @param msg - The error message to throw if the condition is false.
+ * @throws {Error} If the condition is false.
+ * @description Throws an error if the condition is false.
+ * Important: The `asserts condition` return type informs TypeScript
+ * that the condition must be true after this call if no error is thrown.
+ */
+export function assert(condition: unknown, msg?: string): asserts condition {
+  if (!condition) {
+    throw new Error(msg || 'Assertion failed: Condition should be truthy.');
+  }
+}