addListener(): Allow for null | undefined targets. Created new `noo…

…p()` helper.

.changeset/shy-plants-study.md

@@ -0,0 +1,6 @@
+---
+'@finsweet/ts-utils': minor
+---
+
+- `addListener()`: Allow for null | undefined targets. If that's the case, no events will be added and the return callback will be a simple `noop`.
+- Created new `noop()` helper, it literally does nothing.

src/helpers/addListener.ts

@@ -1,3 +1,5 @@
+import { noop } from './noop';
+
 /**
  * Adds an event listener to an element.
  * @returns A callback to remove the event listener from the element.
@@ -25,7 +27,14 @@ export function addListener<
     : Type extends keyof ElementEventMap
     ? (this: Element, ev: ElementEventMap[Type]) => unknown
     : EventListenerOrEventListenerObject
->(target: TargetInterface, type: Type, listener: Listener, options?: boolean | AddEventListenerOptions): () => void {
+>(
+  target: TargetInterface | null | undefined,
+  type: Type,
+  listener: Listener,
+  options?: boolean | AddEventListenerOptions
+): () => void {
+  if (!target) return noop;
+
   target.addEventListener(type, listener, options);
 
   return () => target.removeEventListener(type, listener, options);

src/helpers/index.ts

@@ -12,6 +12,7 @@ export { getObjectEntries } from './getObjectEntries';
 export { getObjectKeys } from './getObjectKeys';
 export { isScrollable } from './isScrollable';
 export { isVisible } from './isVisible';
+export { noop } from './noop';
 export { queryElement } from './queryElement';
 export { removeChildElements } from './removeChildElements';
 export { removeSpaces } from './removeSpaces';

src/helpers/noop.ts

@@ -0,0 +1,7 @@
+/* eslint-disable @typescript-eslint/no-empty-function */
+
+/**
+ * No operation.
+ * It literally does nothing.
+ */
+export const noop = () => {};