⭐️New: Add vue/component-name-in-template-casing (#397)

* Add Vue.extend support, add missing info about Vue.mixin check in readme

* Docs: fixes wording in docs (#372)

* Fix: fix script-indent to prevent removing <script> tag (fixes #367) (#374)

*  [Update] Make `vue/max-attributes-per-line` fixable (#380)

* [Update] Make `vue/max-attributes-per-line` fixable

* [fix] bug and style

* [fix] Switch indent calculation method with node and attribute

* [fix] don't handle indentation

* [add] autofix test max-attributes-per-line.js

* Update: make `vue/order-in-components` fixable (#381)

* [Update] Make `vue/order-in-components` fixable

This Commit makes `vue/order-in-components` fixable.
In case of `The "A" property should be above the "B" property` error, autofix will move A before B

* [fix] fail test at [email protected]

* [fix] If there is a possibility of a side effect, don't autofix

* [fix] failed test at node v4

* [update] use Traverser

* [fix] failed test [email protected]

* [fix] I used `output: null` to specify "not fix"

* [New] Add `vue/component-name-in-template-casing`

* [update] documents

* [fix] require-meta-docs-url

* [fix] failed tests

* [fix] review contents

* Default case to constant. and used it. `const defaultCase = 'PascalCase'`
* `'category'` to `undefined`
* Add empty line for clarity
* I used object shorthand. `caseType: caseType` to `caseType`

* [fix] No deletes space and attributes of endTag

* [fix] Remove test unnecessary option

* [fix] lint error caused by merging the master for conflict resolution

* Add ignores option.

* Fixed that extra differences.

* update docs link

* Update formatting

Author: ota-meshi

README.md

@@ -190,6 +190,7 @@ Enforce all the rules in this category, as well as all higher priority rules, wi
 |    | Rule ID | Description |
 |:---|:--------|:------------|
 | :wrench: | [vue/attribute-hyphenation](./docs/rules/attribute-hyphenation.md) | enforce attribute naming style on custom components in template |
+| :wrench: | [vue/component-name-in-template-casing](./docs/rules/component-name-in-template-casing.md) | enforce specific casing for the component naming style in template |
 | :wrench: | [vue/html-closing-bracket-newline](./docs/rules/html-closing-bracket-newline.md) | require or disallow a line break before tag's closing brackets |
 | :wrench: | [vue/html-closing-bracket-spacing](./docs/rules/html-closing-bracket-spacing.md) | require or disallow a space before tag's closing brackets |
 | :wrench: | [vue/html-end-tags](./docs/rules/html-end-tags.md) | enforce end tag style |

docs/rules/component-name-in-template-casing.md

@@ -0,0 +1,74 @@
+# enforce specific casing for the component naming style in template (vue/component-name-in-template-casing)
+
+- :gear: This rule is included in `"plugin:vue/strongly-recommended"` and `"plugin:vue/recommended"`.
+- :wrench: The `--fix` option on the [command line](http://eslint.org/docs/user-guide/command-line-interface#fix) can automatically fix some of the problems reported by this rule.
+
+Define a style for the component name in template casing for consistency purposes.
+
+## :book: Rule Details
+
+:+1: Examples of **correct** code for `PascalCase`:
+
+```html
+<template>
+  <TheComponent />
+</template>
+```
+
+:-1: Examples of **incorrect** code for `PascalCase`:
+
+```html
+<template>
+  <the-component />
+  <theComponent />
+  <The-component />
+</template>
+```
+
+:+1: Examples of **correct** code for `kebab-case`:
+
+```html
+<template>
+  <the-component />
+</template>
+```
+
+:-1: Examples of **incorrect** code for `kebab-case`:
+
+```html
+<template>
+  <TheComponent />
+  <theComponent />
+  <Thecomponent />
+  <The-component />
+</template>
+```
+
+## :wrench: Options
+
+Default casing is set to `PascalCase`.
+
+```json
+  "vue/component-name-in-template-casing": ["error",
+    "PascalCase|kebab-case",
+    {
+      "ignores": []
+    }
+  ]
+```
+
+- `ignores` (`string[]`) ... The element name to ignore. Sets the element name to allow. For example, a custom element or a non-Vue component.
+
+
+:+1: Examples of **correct** code for `{ignores: ["custom-element"]}`:
+
+```html
+<template>
+  <custom-element></custom-element>
+  <TheComponent/>
+</template>
+```
+
+## Related links
+
+- [Style guide - Component name casing in templates](https://vuejs.org/v2/style-guide/#Component-name-casing-in-templates-strongly-recommended)

lib/configs/strongly-recommended.js

@@ -7,6 +7,7 @@ module.exports = {
   extends: require.resolve('./essential'),
   rules: {
     'vue/attribute-hyphenation': 'error',
+    'vue/component-name-in-template-casing': 'error',
     'vue/html-closing-bracket-newline': 'error',
     'vue/html-closing-bracket-spacing': 'error',
     'vue/html-end-tags': 'error',

lib/index.js

@@ -10,6 +10,7 @@ module.exports = {
     'attribute-hyphenation': require('./rules/attribute-hyphenation'),
     'attributes-order': require('./rules/attributes-order'),
     'comment-directive': require('./rules/comment-directive'),
+    'component-name-in-template-casing': require('./rules/component-name-in-template-casing'),
     'html-closing-bracket-newline': require('./rules/html-closing-bracket-newline'),
     'html-closing-bracket-spacing': require('./rules/html-closing-bracket-spacing'),
     'html-end-tags': require('./rules/html-end-tags'),

lib/rules/component-name-in-template-casing.js

@@ -0,0 +1,108 @@
+/**
+ * @author Yosuke Ota
+ * issue https://github.com/vuejs/eslint-plugin-vue/issues/250
+ */
+'use strict'
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+const utils = require('../utils')
+const casing = require('../utils/casing')
+
+const allowedCaseOptions = ['PascalCase', 'kebab-case']
+const defaultCase = 'PascalCase'
+
+// ------------------------------------------------------------------------------
+// Rule Definition
+// ------------------------------------------------------------------------------
+
+module.exports = {
+  meta: {
+    docs: {
+      description: 'enforce specific casing for the component naming style in template',
+      category: undefined, // strongly-recommended
+      url: 'https://github.com/vuejs/eslint-plugin-vue/blob/v5.0.0-beta.1/docs/rules/component-name-in-template-casing.md'
+    },
+    fixable: 'code',
+    schema: [
+      {
+        enum: allowedCaseOptions
+      },
+      {
+        type: 'object',
+        properties: {
+          ignores: {
+            type: 'array',
+            items: { type: 'string' },
+            uniqueItems: true,
+            additionalItems: false
+          }
+        },
+        additionalProperties: false
+      }
+    ]
+  },
+
+  create (context) {
+    const caseOption = context.options[0]
+    const options = context.options[1] || {}
+    const caseType = allowedCaseOptions.indexOf(caseOption) !== -1 ? caseOption : defaultCase
+    const ignores = options.ignores || []
+    const tokens = context.parserServices.getTemplateBodyTokenStore && context.parserServices.getTemplateBodyTokenStore()
+    const sourceCode = context.getSourceCode()
+
+    let hasInvalidEOF = false
+
+    return utils.defineTemplateBodyVisitor(context, {
+      'VElement' (node) {
+        if (hasInvalidEOF) {
+          return
+        }
+
+        if (!utils.isCustomComponent(node)) {
+          return
+        }
+
+        const name = node.rawName
+        if (ignores.indexOf(name) >= 0) {
+          return
+        }
+        const casingName = casing.getConverter(caseType)(name)
+        if (casingName !== name) {
+          const startTag = node.startTag
+          const open = tokens.getFirstToken(startTag)
+
+          context.report({
+            node: open,
+            loc: open.loc,
+            message: 'Component name "{{name}}" is not {{caseType}}.',
+            data: {
+              name,
+              caseType
+            },
+            fix: fixer => {
+              const endTag = node.endTag
+              if (!endTag) {
+                return fixer.replaceText(open, `<${casingName}`)
+              }
+              const endTagOpen = tokens.getFirstToken(endTag)
+              // If we can upgrade requirements to `eslint@>4.1.0`, this code can be replaced by:
+              // return [
+              //   fixer.replaceText(open, `<${casingName}`),
+              //   fixer.replaceText(endTagOpen, `</${casingName}`)
+              // ]
+              const code = `<${casingName}${sourceCode.text.slice(open.range[1], endTagOpen.range[0])}</${casingName}`
+              return fixer.replaceTextRange([open.range[0], endTagOpen.range[1]], code)
+            }
+          })
+        }
+      }
+    }, {
+      Program (node) {
+        hasInvalidEOF = utils.hasInvalidEOF(node)
+      }
+    })
+  }
+}