Extract rule: template-require-input-label

Author: NullVoxPopuli

README.md

@@ -197,6 +197,7 @@ rules in templates can be disabled with eslint directives with mustache or html
 | [template-no-nested-interactive](docs/rules/template-no-nested-interactive.md)                   | disallow nested interactive elements                                             |    |    |    |
 | [template-no-nested-landmark](docs/rules/template-no-nested-landmark.md)                         | disallow nested landmark elements                                                |    |    |    |
 | [template-no-pointer-down-event-binding](docs/rules/template-no-pointer-down-event-binding.md)   | disallow pointer down event bindings                                             |    |    |    |
+| [template-require-input-label](docs/rules/template-require-input-label.md)                       | require label for form input elements                                            |    |    |    |
 
 ### Best Practices
 

docs/rules/template-require-input-label.md

@@ -0,0 +1,67 @@
+# ember/template-require-input-label
+
+<!-- end auto-generated rule header -->
+
+Require form input elements to have an associated label for accessibility.
+
+## Rule Details
+
+This rule enforces that input, textarea, and select elements have a way to be labeled, either through an `id` attribute (which can be referenced by a `<label for="...">`) or through `aria-label` or `aria-labelledby` attributes.
+
+## Examples
+
+Examples of **incorrect** code for this rule:
+
+```gjs
+<template>
+  <input type="text" />
+</template>
+
+<template>
+  <textarea></textarea>
+</template>
+
+<template>
+  <select>
+    <option>Option 1</option>
+  </select>
+</template>
+```
+
+Examples of **correct** code for this rule:
+
+```gjs
+<template>
+  <label for="name">Name:</label>
+  <input id="name" type="text" />
+</template>
+
+<template>
+  <input aria-label="Name" type="text" />
+</template>
+
+<template>
+  <input aria-labelledby="name-label" type="text" />
+</template>
+
+<template>
+  <input type="hidden" />
+</template>
+```
+
+## Migration
+
+- the recommended fix is to add an associated label element.
+- another option is to add an aria-label to the input element.
+- wrapping the input element in a label element is also allowed; however this is less flexible for styling purposes, so use with awareness.
+
+## Options
+
+| Name        | Type       | Default | Description                                                          |
+| ----------- | ---------- | ------- | -------------------------------------------------------------------- |
+| `labelTags` | `string[]` | `[]`    | Additional tag names to treat as label elements (besides `<label>`). |
+
+## References
+
+- [WCAG 2.1 - Labels or Instructions](https://www.w3.org/WAI/WCAG21/Understanding/labels-or-instructions.html)
+- [MDN - aria-label](https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Attributes/aria-label)

lib/rules/template-require-input-label.js

@@ -0,0 +1,153 @@
+function hasAttr(node, name) {
+  return node.attributes?.some((a) => a.name === name);
+}
+
+/** @type {import('eslint').Rule.RuleModule} */
+module.exports = {
+  meta: {
+    type: 'suggestion',
+    docs: {
+      description: 'require label for form input elements',
+      category: 'Accessibility',
+      url: 'https://github.com/ember-cli/eslint-plugin-ember/tree/master/docs/rules/template-require-input-label.md',
+      templateMode: 'both',
+    },
+    schema: [
+      {
+        type: 'object',
+        properties: {
+          labelTags: {
+            type: 'array',
+            items: { type: 'string' },
+          },
+        },
+        additionalProperties: false,
+      },
+    ],
+    messages: {
+      requireLabel: 'Input elements should have an associated label.',
+      multipleLabels: 'Input element has multiple labelling mechanisms.',
+    },
+    originallyFrom: {
+      name: 'ember-template-lint',
+      rule: 'lib/rules/require-input-label.js',
+      docs: 'docs/rule/require-input-label.md',
+      tests: 'test/unit/rules/require-input-label-test.js',
+    },
+  },
+
+  create(context) {
+    const options = context.options[0] || {};
+    const customLabelTags = options.labelTags || [];
+    const labelTags = new Set(['label', ...customLabelTags]);
+    const elementStack = [];
+
+    function hasValidLabelParent() {
+      for (let i = elementStack.length - 1; i >= 0; i--) {
+        const entry = elementStack[i];
+        if (labelTags.has(entry.tag)) {
+          // Custom label tags (not 'label') are always considered valid
+          if (entry.tag !== 'label') {
+            return true;
+          }
+          // For 'label' tag, valid only if it has more than one child (text content + input)
+          const children = entry.node.children || [];
+          return children.length > 1;
+        }
+      }
+      return false;
+    }
+
+    return {
+      GlimmerElementNode(node) {
+        elementStack.push({ tag: node.tag, node });
+
+        const tagName = node.tag?.toLowerCase();
+        if (tagName !== 'input' && tagName !== 'textarea' && tagName !== 'select') {
+          return;
+        }
+
+        // Skip if input has type="hidden"
+        const typeAttr = node.attributes?.find((a) => a.name === 'type');
+        if (typeAttr?.value?.type === 'GlimmerTextNode' && typeAttr.value.chars === 'hidden') {
+          return;
+        }
+
+        // Skip if has ...attributes (can't determine labelling)
+        if (hasAttr(node, '...attributes')) {
+          return;
+        }
+
+        let labelCount = 0;
+        const validLabel = hasValidLabelParent();
+        if (validLabel) {
+          labelCount++;
+        }
+
+        const hasId = hasAttr(node, 'id');
+        const hasAriaLabel = hasAttr(node, 'aria-label');
+        const hasAriaLabelledBy = hasAttr(node, 'aria-labelledby');
+        if (hasId) {
+          labelCount++;
+        }
+        if (hasAriaLabel) {
+          labelCount++;
+        }
+        if (hasAriaLabelledBy) {
+          labelCount++;
+        }
+
+        if (labelCount === 1) {
+          return;
+        }
+
+        // Special case: label parent + id is OK (common pattern)
+        if (validLabel && hasId) {
+          return;
+        }
+
+        context.report({
+          node,
+          messageId: labelCount === 0 ? 'requireLabel' : 'multipleLabels',
+        });
+      },
+      'GlimmerElementNode:exit'() {
+        elementStack.pop();
+      },
+
+      GlimmerMustacheStatement(node) {
+        const name = node.path?.original;
+        if (name !== 'input' && name !== 'textarea') {
+          return;
+        }
+
+        const pairs = node.hash?.pairs || [];
+
+        function hasPair(key) {
+          return pairs.some((p) => p.key === key);
+        }
+
+        // Skip if type="hidden" (literal string only)
+        const typePair = pairs.find((p) => p.key === 'type');
+        if (typePair?.value?.type === 'GlimmerStringLiteral' && typePair.value.value === 'hidden') {
+          return;
+        }
+
+        // If in a valid label, it's valid
+        if (hasValidLabelParent()) {
+          return;
+        }
+
+        // If has id, it's valid
+        if (hasPair('id')) {
+          return;
+        }
+
+        context.report({
+          node,
+          messageId: 'requireLabel',
+        });
+      },
+    };
+  },
+};