feat: add slot-name-casing rule (#2620)

Co-authored-by: Flo Edelmann <git@flo-edelmann.de>

docs/rules/index.md

@@ -281,8 +281,9 @@ For example:
 | [vue/require-prop-comment](./require-prop-comment.md) | require props to have a comment |  | :hammer: |
 | [vue/require-typed-object-prop](./require-typed-object-prop.md) | enforce adding type declarations to object props | :bulb: | :hammer: |
 | [vue/require-typed-ref](./require-typed-ref.md) | require `ref` and `shallowRef` functions to be strongly typed |  | :hammer: |
-| [vue/restricted-component-names](./restricted-component-names.md) | enforce using only specific in component names |  | :warning: |
+| [vue/restricted-component-names](./restricted-component-names.md) | enforce using only specific component names |  | :warning: |
 | [vue/script-indent](./script-indent.md) | enforce consistent indentation in `<script>` | :wrench: | :lipstick: |
+| [vue/slot-name-casing](./slot-name-casing.md) | enforce specific casing for slot names |  | :hammer: |
 | [vue/sort-keys](./sort-keys.md) | enforce sort-keys in a manner that is compatible with order-in-components |  | :hammer: |
 | [vue/static-class-names-order](./static-class-names-order.md) | enforce static class names order | :wrench: | :hammer: |
 | [vue/v-for-delimiter-style](./v-for-delimiter-style.md) | enforce `v-for` directive's delimiter style | :wrench: | :lipstick: |

docs/rules/restricted-component-names.md

@@ -2,12 +2,12 @@
 pageClass: rule-details
 sidebarDepth: 0
 title: vue/restricted-component-names
-description: enforce using only specific in component names
+description: enforce using only specific component names
 ---
 
 # vue/restricted-component-names
 
-> enforce using only specific in component names
+> enforce using only specific component names
 
 - :exclamation: <badge text="This rule has not been released yet." vertical="middle" type="error"> _**This rule has not been released yet.**_ </badge>
 

docs/rules/slot-name-casing.md

@@ -0,0 +1,88 @@
+---
+pageClass: rule-details
+sidebarDepth: 0
+title: vue/slot-name-casing
+description: enforce specific casing for slot names
+---
+
+# vue/slot-name-casing
+
+> enforce specific casing for slot names
+
+- :exclamation: <badge text="This rule has not been released yet." vertical="middle" type="error"> _**This rule has not been released yet.**_ </badge>
+
+## :book: Rule Details
+
+This rule enforces proper casing of slot names in Vue components.
+
+<eslint-code-block :rules="{'vue/slot-name-casing': ['error']}">
+
+```vue
+<template>
+  <!-- ✓ GOOD -->
+  <slot name="foo" />
+  <slot name="fooBar" />
+
+  <!-- ✗ BAD -->
+  <slot name="foo-bar" />
+  <slot name="foo_bar" />
+  <slot name="foo:bar" />
+</template>
+```
+
+</eslint-code-block>
+
+## :wrench: Options
+
+```json
+{
+  "vue/slot-name-casing": ["error", "camelCase" | "kebab-case" | "singleword"]
+}
+```
+
+- `"camelCase"` (default) ... Enforce slot name to be in camel case.
+- `"kebab-case"` ... Enforce slot name to be in kebab case.
+- `"singleword"` ... Enforce slot name to be a single word.
+
+### `"kebab-case"`
+
+<eslint-code-block :rules="{'vue/prop-name-casing': ['error', 'kebab-case']}">
+
+```vue
+<template>
+  <!-- ✓ GOOD -->
+  <slot name="foo" />
+  <slot name="foo-bar" />
+
+  <!-- ✗ BAD -->
+  <slot name="fooBar" />
+  <slot name="foo_bar" />
+  <slot name="foo:bar" />
+</template>
+```
+
+</eslint-code-block>
+
+### `"singleword"`
+
+<eslint-code-block :rules="{'vue/prop-name-casing': ['error', 'singleword']}">
+
+```vue
+<template>
+  <!-- ✓ GOOD -->
+  <slot name="foo" />
+
+  <!-- ✗ BAD -->
+  <slot name="foo-bar" />
+  <slot name="fooBar" />
+  <slot name="foo_bar" />
+  <slot name="foo:bar" />
+</template>
+```
+
+</eslint-code-block>
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/vuejs/eslint-plugin-vue/blob/master/lib/rules/slot-name-casing.js)
+- [Test source](https://github.com/vuejs/eslint-plugin-vue/blob/master/tests/lib/rules/slot-name-casing.js)

lib/index.js

@@ -237,6 +237,7 @@ const plugin = {
     'script-indent': require('./rules/script-indent'),
     'script-setup-uses-vars': require('./rules/script-setup-uses-vars'),
     'singleline-html-element-content-newline': require('./rules/singleline-html-element-content-newline'),
+    'slot-name-casing': require('./rules/slot-name-casing'),
     'sort-keys': require('./rules/sort-keys'),
     'space-in-parens': require('./rules/space-in-parens'),
     'space-infix-ops': require('./rules/space-infix-ops'),

lib/rules/slot-name-casing.js

@@ -0,0 +1,82 @@
+/**
+ * @author Wayne Zhang
+ * See LICENSE file in root directory for full license.
+ */
+'use strict'
+
+const utils = require('../utils')
+const casing = require('../utils/casing')
+
+/**
+ * @typedef { 'camelCase' | 'kebab-case' | 'singleword' } OptionType
+ * @typedef { (str: string) => boolean } CheckerType
+ */
+
+/**
+ * Checks whether the given string is a single word.
+ * @param {string} str
+ * @return {boolean}
+ */
+function isSingleWord(str) {
+  return /^[a-z]+$/u.test(str)
+}
+
+/** @type {OptionType[]} */
+const allowedCaseOptions = ['camelCase', 'kebab-case', 'singleword']
+
+module.exports = {
+  meta: {
+    type: 'suggestion',
+    docs: {
+      description: 'enforce specific casing for slot names',
+      categories: undefined,
+      url: 'https://eslint.vuejs.org/rules/slot-name-casing.html'
+    },
+    fixable: null,
+    schema: [
+      {
+        enum: allowedCaseOptions
+      }
+    ],
+    messages: {
+      invalidCase: 'Slot name "{{name}}" is not {{caseType}}.'
+    }
+  },
+  /** @param {RuleContext} context */
+  create(context) {
+    const option = context.options[0]
+
+    /** @type {OptionType} */
+    const caseType = allowedCaseOptions.includes(option) ? option : 'camelCase'
+
+    /** @type {CheckerType} */
+    const checker =
+      caseType === 'singleword' ? isSingleWord : casing.getChecker(caseType)
+
+    /** @param {VAttribute} node */
+    function processSlotNode(node) {
+      const name = node.value?.value
+      if (name && !checker(name)) {
+        context.report({
+          node,
+          loc: node.loc,
+          messageId: 'invalidCase',
+          data: {
+            name,
+            caseType
+          }
+        })
+      }
+    }
+
+    return utils.defineTemplateBodyVisitor(context, {
+      /** @param {VElement} node */
+      "VElement[name='slot']"(node) {
+        const slotName = utils.getAttribute(node, 'name')
+        if (slotName) {
+          processSlotNode(slotName)
+        }
+      }
+    })
+  }
+}

tests/lib/rules/slot-name-casing.js

@@ -0,0 +1,148 @@
+/**
+ * @author WayneZhang
+ * See LICENSE file in root directory for full license.
+ */
+'use strict'
+
+const RuleTester = require('../../eslint-compat').RuleTester
+const rule = require('../../../lib/rules/slot-name-casing')
+
+const tester = new RuleTester({
+  languageOptions: {
+    parser: require('vue-eslint-parser'),
+    ecmaVersion: 2020,
+    sourceType: 'module'
+  }
+})
+
+tester.run('slot-name-casing', rule, {
+  valid: [
+    `<template><slot key="foo" /></template>`,
+    `<template><slot name /></template>`,
+    `<template><slot name="foo" /></template>`,
+    `<template><slot name="fooBar" /></template>`,
+    `<template><slot :name="fooBar" /></template>`,
+    {
+      filename: 'test.vue',
+      code: `
+        <template>
+          <slot name="foo" />
+          <slot name="foo-bar" />
+          <slot :name="fooBar" />
+        </template>
+      `,
+      options: ['kebab-case']
+    },
+    {
+      filename: 'test.vue',
+      code: `
+        <template>
+          <slot name="foo" />
+          <slot :name="fooBar" />
+        </template>
+      `,
+      options: ['singleword']
+    }
+  ],
+  invalid: [
+    {
+      filename: 'test.vue',
+      code: `
+        <template>
+          <slot name="foo-bar" />
+          <slot name="foo-Bar_baz" />
+        </template>
+      `,
+      errors: [
+        {
+          messageId: 'invalidCase',
+          data: {
+            name: 'foo-bar',
+            caseType: 'camelCase'
+          },
+          line: 3,
+          column: 17
+        },
+        {
+          messageId: 'invalidCase',
+          data: {
+            name: 'foo-Bar_baz',
+            caseType: 'camelCase'
+          },
+          line: 4,
+          column: 17
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+        <template>
+          <slot name="fooBar" />
+          <slot name="foo-Bar_baz" />
+        </template>
+      `,
+      options: ['kebab-case'],
+      errors: [
+        {
+          messageId: 'invalidCase',
+          data: {
+            name: 'fooBar',
+            caseType: 'kebab-case'
+          },
+          line: 3,
+          column: 17
+        },
+        {
+          messageId: 'invalidCase',
+          data: {
+            name: 'foo-Bar_baz',
+            caseType: 'kebab-case'
+          },
+          line: 4,
+          column: 17
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+        <template>
+          <slot name="foo-bar" />
+          <slot name="fooBar" />
+          <slot name="foo-Bar_baz" />
+        </template>
+      `,
+      options: ['singleword'],
+      errors: [
+        {
+          messageId: 'invalidCase',
+          data: {
+            name: 'foo-bar',
+            caseType: 'singleword'
+          },
+          line: 3,
+          column: 17
+        },
+        {
+          messageId: 'invalidCase',
+          data: {
+            name: 'fooBar',
+            caseType: 'singleword'
+          },
+          line: 4,
+          column: 17
+        },
+        {
+          messageId: 'invalidCase',
+          data: {
+            name: 'foo-Bar_baz',
+            caseType: 'singleword'
+          },
+          line: 5,
+          column: 17
+        }
+      ]
+    }
+  ]
+})