Add expectElements (strict $$) (#31)

index.ts

@@ -151,4 +151,34 @@ function $$<Selected extends Element>(
 	return [...elements]; // Convert to array
 }
 
-export {$, $$, lastElement, elementExists, expectElement};
+/**
+ * @param selectors       One or more CSS selectors separated by commas
+ * @param [baseElements]  The element or list of elements to look inside of
+ * @return                An array of elements found
+ */
+function expectElements<Selector extends string, Selected extends Element = ParseSelector<Selector, HTMLElement>>(
+	selectors: Selector | readonly Selector[],
+	baseElements?: BaseElements
+): Selected[];
+function expectElements<Selected extends Element = HTMLElement>(
+	selectors: string | readonly string[],
+	baseElements?: BaseElements
+): Selected[];
+function expectElements<Selected extends Element>(
+	selectors: string | readonly string[],
+	baseElements?: BaseElements,
+): Selected[] {
+	// Shortcut with specified-but-null baseElements
+	if (arguments.length === 2 && !baseElements) {
+		throw new ElementNotFoundError('Expected elements not found because the base is specified but null');
+	}
+
+	const elements = $$<Selected>(selectors, baseElements);
+	if (elements.length > 0) {
+		return elements;
+	}
+
+	throw new ElementNotFoundError(`Expected elements not found: ${String(selectors)}`);
+}
+
+export {$, $$, lastElement, elementExists, expectElement, expectElements};

readme.md

@@ -77,10 +77,14 @@ $$('.foo', [baseElement1, baseElement2]);
 The strict export will throw an error if the element is not found, instead of returning `undefined`. This is also reflected in the types, which are non-nullable:
 
 ```ts
-import {$, $optional} from 'select-dom/strict.js';
+import {$, $optional, $$, $$optional} from 'select-dom/strict.js';
 
 const must: HTMLAnchorElement = $('.foo a[href=bar]'); //
 const optional: HTMLAnchorElement | undefined = $optional('.foo a[href=bar]');
+
+
+const oneOrMore: HTMLAnchorElement[] = $$('.foo a[href=bar]'); //
+const zeroOrMore: HTMLAnchorElement[] = $$optional('.foo a[href=bar]');
 ```
 
 ## Related

strict.ts

@@ -1 +1,6 @@
-export {$ as $optional, expectElement as $} from './index.js';
+export {
+	$ as $optional,
+	$$ as $$optional,
+	expectElement as $,
+	expectElements as $$,
+} from './index.js';