a11y: Add role-has-required-aria-props rule

package.json

@@ -124,12 +124,14 @@
     "@rollup/plugin-typescript": "^2.0.1",
     "@rollup/plugin-virtual": "^2.0.0",
     "@sveltejs/eslint-config": "github:sveltejs/eslint-config#v5.8.0",
+    "@types/aria-query": "^5.0.0",
     "@types/mocha": "^7.0.0",
     "@types/node": "^8.10.53",
     "@typescript-eslint/eslint-plugin": "^5.22.0",
     "@typescript-eslint/parser": "^5.22.0",
     "acorn": "^8.4.1",
     "agadoo": "^1.1.0",
+    "aria-query": "^5.0.0",
     "code-red": "^0.2.5",
     "css-tree": "^1.1.2",
     "eslint": "^8.0.0",

site/content/docs/05-accessibility-warnings.md

@@ -54,6 +54,17 @@ The following elements are visually distracting: `<marquee>` and `<blink>`.
 
 ---
 
+### `role-has-required-aria-props`
+
+Elements with ARIA roles must have all required attributes for that role.
+
+```sv
+<!-- A11y: A11y: Elements with the ARIA role "checkbox" must have the following attributes defined: "aria-checked" -->
+<span role="checkbox" aria-labelledby="foo" tabindex="0"></span>
+```
+
+---
+
 ### `a11y-hidden`
 
 Certain DOM elements are useful for screen reader navigation and should not be hidden.

src/compiler/compile/compiler_warnings.ts

@@ -80,6 +80,10 @@ export default {
 		code: 'a11y-no-redundant-roles',
 		message: `A11y: Redundant role '${role}'`
 	}),
+	a11y_role_has_required_aria_props: (role: string, props: string[]) => ({
+		code: 'a11y-role-has-required-aria-props',
+		message: `A11y: Elements with the ARIA role "${role}" must have the following attributes defined: ${props.map(name => `"${name}"`).join(', ')}`
+	}),
 	a11y_accesskey: {
 		code: 'a11y-accesskey',
 		message: 'A11y: Avoid using accesskey'

src/compiler/compile/nodes/Element.ts

@@ -23,6 +23,7 @@ import { string_literal } from '../utils/stringify';
 import { Literal } from 'estree';
 import compiler_warnings from '../compiler_warnings';
 import compiler_errors from '../compiler_errors';
+import { ARIARoleDefintionKey, roles } from 'aria-query';
 
 const svg = /^(?:altGlyph|altGlyphDef|altGlyphItem|animate|animateColor|animateMotion|animateTransform|circle|clipPath|color-profile|cursor|defs|desc|discard|ellipse|feBlend|feColorMatrix|feComponentTransfer|feComposite|feConvolveMatrix|feDiffuseLighting|feDisplacementMap|feDistantLight|feDropShadow|feFlood|feFuncA|feFuncB|feFuncG|feFuncR|feGaussianBlur|feImage|feMerge|feMergeNode|feMorphology|feOffset|fePointLight|feSpecularLighting|feSpotLight|feTile|feTurbulence|filter|font|font-face|font-face-format|font-face-name|font-face-src|font-face-uri|foreignObject|g|glyph|glyphRef|hatch|hatchpath|hkern|image|line|linearGradient|marker|mask|mesh|meshgradient|meshpatch|meshrow|metadata|missing-glyph|mpath|path|pattern|polygon|polyline|radialGradient|rect|set|solidcolor|stop|svg|switch|symbol|text|textPath|tref|tspan|unknown|use|view|vkern)$/;
 
@@ -407,9 +408,9 @@ export default class Element extends Node {
 	}
 
 	validate_attributes_a11y() {
-		const { component } = this;
+		const { component, attributes } = this;
 
-		this.attributes.forEach(attribute => {
+		attributes.forEach(attribute => {
 			if (attribute.is_spread) return;
 
 			const name = attribute.name.toLowerCase();
@@ -462,6 +463,17 @@ export default class Element extends Node {
 						component.warn(attribute, compiler_warnings.a11y_no_redundant_roles(value));
 					}
 				}
+
+				// role-has-required-aria-props
+				const role = roles.get(value as ARIARoleDefintionKey);
+				if (role) {
+					const required_role_props = Object.keys(role.requiredProps);
+					const has_missing_props = required_role_props.some(prop => !attributes.find(a => a.name === prop));
+
+					if (has_missing_props) {
+						component.warn(attribute, compiler_warnings.a11y_role_has_required_aria_props(value as string, required_role_props));
+					}
+				}
 			}
 
 			// no-access-key