Implement the custom options helper (closes #92)

module/helpers/options.mjs

@@ -0,0 +1,32 @@
+/**
+ * @typedef {object} Option
+ * @property {string} [label]
+ * @property {string|number} value
+ * @property {boolean} [disabled]
+ */
+
+/**
+ * @param {string | number} selected
+ * @param {Array<Option | string>} opts
+ */
+export function options(selected, opts) {
+	selected = Handlebars.escapeExpression(selected);
+	const htmlOptions = [];
+
+	for (let opt of opts) {
+		if (foundry.utils.getType(opt) === "string") {
+			opt = { label: opt, value: opt };
+		};
+		opt.value = Handlebars.escapeExpression(opt.value);
+		htmlOptions.push(
+			`<option
+				value="${opt.value}"
+				${selected === opt.value ? "selected" : ""}
+				${opt.disabled ? "disabled" : ""}
+			>
+				${opt.label}
+			</option>`
+		);
+	};
+	return htmlOptions.join(`\n`);
+};