stratos/views/reports.hbs

<section class='adminSection'>
	<div class='adminItem'>
		<h2>Generate Report</h2>
		<div class='formContainer'>
			<form action='/admin/report/generate' method='post'>
				<select name='type' id='type' required>
					<option disabled hidden selected value=''>Select report type</option>
					{{#each types}}
						<option value='{{key}}'>{{value}}</option>
					{{/each}}
				</select>

				<select name='target' id='target' required>
					<option disabled hidden selected value=''>Select report target</option>
				</select>

				<input type='submit' class='btn btn--primary btn--full' value='Generate report'/>
			</form>
		</div>
	</div>
</section>

<script>
	const targets = {{{targets}}};
	const cache = {};

	const typeSelect = document.querySelector('form select[name="type"]');
	const targetSelect = document.querySelector('form select[name="target"]');

	typeSelect.addEventListener('change', (e) => {
		const type = typeSelect.value;

		const placeholder = document.createElement('option');
		placeholder.setAttribute('disabled', true);
		placeholder.setAttribute('hidden', true);
		placeholder.setAttribute('selected', true);
		placeholder.setAttribute('value', '');
		placeholder.innerText = 'Select report target';

		if (!cache[type]) {
			cache[type] = targets[type].map(({ id, name }) => {
				const elem = document.createElement('option');
				elem.setAttribute('value', id);
				elem.innerText = name;

				return elem;
			});
		}

		targetSelect.replaceChildren(placeholder, ...cache[type]);
	});
</script>