Add accessible-emoji a11y check

src/compiler/compile/nodes/Text.ts

@@ -24,6 +24,7 @@ export default class Text extends Node {
 		super(component, parent, scope, info);
 		this.data = info.data;
 		this.synthetic = info.synthetic || false;
+		this.validate();
 	}
 
 	should_skip() {
@@ -42,4 +43,35 @@ export default class Text extends Node {
 
 		return parent_element.namespace || elements_without_text.has(parent_element.name);
 	}
+
+	validate() {
+		const { data, component, parent } = this;
+
+		// https://github.com/mathiasbynens/emoji-regex/blob/master/src/index.js
+		const emoji_regex =/<% emojiSequence %>|\p{Emoji_Presentation}|\p{Emoji}\uFE0F|\p{Emoji_Modifier_Base}/gu;
+
+		if (!emoji_regex.test(data)) return;
+
+		let is_accessible = false;
+
+		if (parent.type === 'Element' && parent.name === 'span') {
+			const { attributes } = parent;
+			const role = parent.get_static_attribute_value('role');
+			const aria_label_index = attributes.findIndex(attr => 
+				attr.type === 'Attribute' &&
+				(attr.name === 'aria-label' || attr.name === 'aria-labelledby') 
+			);
+
+			if (role === 'img' && aria_label_index > -1) {
+				is_accessible = true;
+			}
+		}
+
+		if (!is_accessible) {
+			component.warn(this, {
+				code: 'a11y-accessible-emoji',
+				message: 'A11y: emojis should be wrapped in a <span>, with role="img", and have a description using aria-label or aria-labelledby'
+			});
+		}
+	}
 }

test/validator/samples/a11y-accessible-emoji/input.svelte

@@ -0,0 +1,5 @@
+<span>🐼</span>
+<i role="img" aria-label="Panda">🐼</i>
+
+<!-- this one won't have a warning -->
+<span role="img" aria-label="Panda">🐼</span>

test/validator/samples/a11y-accessible-emoji/warnings.json

@@ -0,0 +1,33 @@
+[
+	{
+		"code": "a11y-accessible-emoji",
+		"message": "A11y: emojis should be wrapped in a <span>, with role=\"img\", and have a description using aria-label or aria-labelledby",
+		"start": {
+			"line": 1,
+			"column": 6,
+			"character": 6
+		},
+		"end": {
+			"line": 1,
+			"column": 8,
+			"character": 8
+		},
+		"pos": 6
+	},
+
+	{
+		"code": "a11y-accessible-emoji",
+		"message": "A11y: emojis should be wrapped in a <span>, with role=\"img\", and have a description using aria-label or aria-labelledby",
+		"start": {
+			"line": 2,
+			"column": 33,
+			"character": 49
+		},
+		"end": {
+			"line": 2,
+			"column": 35,
+			"character": 51
+		},
+		"pos": 49
+	}
+]