only suggest default value for boolean/tristate attributes

Author: Rich-Harris

packages/svelte/messages/compile-warnings/a11y.md

@@ -26,6 +26,12 @@
 
 > Avoid `<%name%>` elements
 
+## a11y_empty_aria_attribute
+
+> '%attribute%' cannot be empty
+
+> '%attribute%' cannot be empty — change it to `%attribute%="%value%"`
+
 ## a11y_figcaption_index
 
 > `<figcaption>` must be first or last child of `<figure>`
@@ -46,10 +52,6 @@
 
 > The value of '%attribute%' must be of type %type%
 
-## a11y_empty_aria_attribute
-
-> '%attribute%' cannot be empty — change it to `%attribute%="true"`
-
 ## a11y_incorrect_aria_attribute_type_boolean
 
 > The value of '%attribute%' must be either 'true' or 'false'

packages/svelte/src/compiler/phases/2-analyze/a11y.js

@@ -605,7 +605,8 @@ function validate_aria_attribute_value(attribute, name, schema, value) {
 	if (value === null) return;
 
 	if (value === true) {
-		w.a11y_empty_aria_attribute(attribute, name);
+		const v = type === 'boolean' || type === 'tristate' ? 'true' : undefined;
+		w.a11y_empty_aria_attribute(attribute, name, v);
 		return;
 	}
 

packages/svelte/src/compiler/warnings.js

@@ -100,6 +100,16 @@ export function a11y_distracting_elements(node, name) {
 	w(node, "a11y_distracting_elements", `Avoid \`<${name}>\` elements`);
 }
 
+/**
+ * '%attribute%' cannot be empty — change it to `%attribute%="%value%"`
+ * @param {null | NodeLike} node
+ * @param {string} attribute
+ * @param {string | undefined | null} [value]
+ */
+export function a11y_empty_aria_attribute(node, attribute, value) {
+	w(node, "a11y_empty_aria_attribute", value ? `'${attribute}' cannot be empty — change it to \`${attribute}="${value}"\`` : `'${attribute}' cannot be empty`);
+}
+
 /**
  * `<figcaption>` must be first or last child of `<figure>`
  * @param {null | NodeLike} node
@@ -143,15 +153,6 @@ export function a11y_incorrect_aria_attribute_type(node, attribute, type) {
 	w(node, "a11y_incorrect_aria_attribute_type", `The value of '${attribute}' must be of type ${type}`);
 }
 
-/**
- * '%attribute%' cannot be empty — change it to `%attribute%="true"`
- * @param {null | NodeLike} node
- * @param {string} attribute
- */
-export function a11y_empty_aria_attribute(node, attribute) {
-	w(node, "a11y_empty_aria_attribute", `'${attribute}' cannot be empty — change it to \`${attribute}="true"\``);
-}
-
 /**
  * The value of '%attribute%' must be either 'true' or 'false'
  * @param {null | NodeLike} node

packages/svelte/tests/validator/samples/a11y-aria-proptypes-integer/warnings.json

@@ -25,7 +25,7 @@
 	},
 	{
 		"code": "a11y_empty_aria_attribute",
-		"message": "'aria-level' cannot be empty — change it to `aria-level=\"true\"`",
+		"message": "'aria-level' cannot be empty",
 		"start": {
 			"line": 4,
 			"column": 5