only enforce static type if input is bound (fixes #620)

src/generators/dom/visitors/Element/Attribute.ts

@@ -22,8 +22,7 @@ export default function visitAttribute(
 	const isIndirectlyBoundValue =
 		name === 'value' &&
 		(node.name === 'option' || // TODO check it's actually bound
-			(node.name === 'input' &&
-				/^(checkbox|radio)$/.test(getStaticAttributeValue(node, 'type'))));
+			(node.name === 'input' && node.attributes.find((attribute: Node) => attribute.type === 'Binding' && /checked|group/.test(attribute.name))));
 
 	const propertyName = isIndirectlyBoundValue
 		? '__value'

src/validate/html/validateElement.ts

@@ -25,6 +25,8 @@ export default function validateElement(validator: Validator, node: Node) {
 						attribute.start
 					);
 				}
+
+				checkTypeAttribute(validator, node);
 			} else if (name === 'checked') {
 				if (node.name !== 'input') {
 					validator.error(
@@ -33,7 +35,7 @@ export default function validateElement(validator: Validator, node: Node) {
 					);
 				}
 
-				if (getType(validator, node) !== 'checkbox') {
+				if (checkTypeAttribute(validator, node) !== 'checkbox') {
 					validator.error(
 						`'checked' binding can only be used with <input type="checkbox">`,
 						attribute.start
@@ -47,7 +49,7 @@ export default function validateElement(validator: Validator, node: Node) {
 					);
 				}
 
-				const type = getType(validator, node);
+				const type = checkTypeAttribute(validator, node);
 
 				if (type !== 'checkbox' && type !== 'radio') {
 					validator.error(
@@ -128,7 +130,7 @@ export default function validateElement(validator: Validator, node: Node) {
 	});
 }
 
-function getType(validator: Validator, node: Node) {
+function checkTypeAttribute(validator: Validator, node: Node) {
 	const attribute = node.attributes.find(
 		(attribute: Node) => attribute.name === 'type'
 	);
@@ -139,7 +141,7 @@ function getType(validator: Validator, node: Node) {
 	}
 
 	if (attribute.value.length > 1 || attribute.value[0].type !== 'Text') {
-		validator.error(`'type attribute cannot be dynamic`, attribute.start);
+		validator.error(`'type' attribute cannot be dynamic if input uses two-way binding`, attribute.start);
 	}
 
 	return attribute.value[0].data;

test/runtime/samples/attribute-dynamic-type/_config.js

@@ -0,0 +1,19 @@
+export default {
+	'skip-ssr': true,
+
+	data: {
+		inputType: 'text',
+		inputValue: 42
+	},
+
+	html: `<input type="text">`,
+
+	test(assert, component, target) {
+		const input = target.querySelector('input');
+		assert.equal(input.type, 'text');
+		assert.equal(input.value, '42');
+
+		component.set({ inputType: 'number' });
+		assert.equal(input.type, 'number');
+	}
+};

test/runtime/samples/attribute-dynamic-type/main.html

@@ -0,0 +1 @@
+<input type='{{inputType}}' value='{{inputValue}}'>

test/validator/samples/binding-input-static-type/errors.json

@@ -0,0 +1,8 @@
+[{
+	"message": "'type' attribute cannot be dynamic if input uses two-way binding",
+	"loc": {
+		"line": 1,
+		"column": 24
+	},
+	"pos": 24
+}]

test/validator/samples/binding-input-static-type/input.html

@@ -0,0 +1 @@
+<input bind:value='foo' type='{{inputType}}'>