static-class-names-order rule (#886)

* class-order rule

* support ascii whitespace, add tests

* polish readme

* polish the rule file

* update rule parser usage

* alphabetize

* npm run update

* fix typo

docs/rules/README.md

@@ -160,6 +160,7 @@ For example:
 | [vue/script-indent](./script-indent.md) | enforce consistent indentation in `<script>` | :wrench: |
 | [vue/space-infix-ops](./space-infix-ops.md) | require spacing around infix operators | :wrench: |
 | [vue/space-unary-ops](./space-unary-ops.md) | enforce consistent spacing before or after unary operators | :wrench: |
+| [vue/static-class-names-order](./static-class-names-order.md) | enforce static class names order | :wrench: |
 | [vue/v-on-function-call](./v-on-function-call.md) | enforce or forbid parentheses after method calls without arguments in `v-on` directives | :wrench: |
 | [vue/v-slot-style](./v-slot-style.md) | enforce `v-slot` directive style | :wrench: |
 | [vue/valid-v-slot](./valid-v-slot.md) | enforce valid `v-slot` directives |  |

docs/rules/static-class-names-order.md

@@ -0,0 +1,37 @@
+---
+pageClass: rule-details
+sidebarDepth: 0
+title: vue/static-class-names-order
+description: enforce static class names order
+---
+# vue/static-class-names-order
+> enforce static class names order
+
+- :wrench: The `--fix` option on the [command line](https://eslint.org/docs/user-guide/command-line-interface#fixing-problems) can automatically fix some of the problems reported by this rule.
+
+### Example
+
+<eslint-code-block fix :rules="{'vue/static-class-names-order': ['error']}">
+
+```vue
+<template>
+  <!-- ✓ GOOD -->
+  <div class="a b"></div>
+
+  <!-- ✗ BAD -->
+  <div class="b a"></div>
+</template>
+```
+
+</eslint-code-block>
+
+## :books: Further reading
+
+- [static-class-names-order]
+
+[static-class-names-order]: https://eslint.org/docs/rules/static-class-names-order
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/vuejs/eslint-plugin-vue/blob/master/lib/rules/static-class-names-order.js)
+- [Test source](https://github.com/vuejs/eslint-plugin-vue/blob/master/tests/lib/rules/static-class-names-order.js)

lib/index.js

@@ -70,6 +70,7 @@ module.exports = {
     'singleline-html-element-content-newline': require('./rules/singleline-html-element-content-newline'),
     'space-infix-ops': require('./rules/space-infix-ops'),
     'space-unary-ops': require('./rules/space-unary-ops'),
+    'static-class-names-order': require('./rules/static-class-names-order'),
     'this-in-template': require('./rules/this-in-template'),
     'use-v-on-exact': require('./rules/use-v-on-exact'),
     'v-bind-style': require('./rules/v-bind-style'),

lib/rules/static-class-names-order.js

@@ -0,0 +1,55 @@
+/**
+* @fileoverview Alphabetizes static class names.
+* @author Maciej Chmurski
+*/
+'use strict'
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+const { defineTemplateBodyVisitor } = require('../utils')
+
+// ------------------------------------------------------------------------------
+// Rule Definition
+// ------------------------------------------------------------------------------
+module.exports = {
+  meta: {
+    type: 'suggestion',
+    docs: {
+      url: 'https://eslint.vuejs.org/rules/static-class-names-order.html',
+      description: 'enforce static class names order',
+      category: undefined
+    },
+    fixable: 'code',
+    schema: []
+  },
+  create: context => {
+    return defineTemplateBodyVisitor(context, {
+      "VAttribute[directive=false][key.name='class']" (node) {
+        const classList = node.value.value
+        const classListWithWhitespace = classList.split(/(\s+)/)
+
+        // Detect and reuse any type of whitespace.
+        let divider = ''
+        if (classListWithWhitespace.length > 1) {
+          divider = classListWithWhitespace[1]
+        }
+
+        const classListNoWhitespace = classListWithWhitespace.filter(className => className.trim() !== '')
+        const classListSorted = classListNoWhitespace.sort().join(divider)
+
+        if (classList !== classListSorted) {
+          context.report({
+            node,
+            loc: node.loc,
+            message: 'Classes should be ordered alphabetically.',
+            fix: (fixer) => fixer.replaceTextRange(
+              [node.value.range[0], node.value.range[1]], `"${classListSorted}"`
+            )
+          })
+        }
+      }
+    })
+  }
+}

tests/lib/rules/static-class-names-order.js

@@ -0,0 +1,77 @@
+/**
+ * @fileoverview enforce ordering of classes
+ * @author Maciej Chmurski
+ */
+'use strict'
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+var rule = require('../../../lib/rules/static-class-names-order')
+var RuleTester = require('eslint').RuleTester
+
+// ------------------------------------------------------------------------------
+// Tests
+// ------------------------------------------------------------------------------
+
+var tester = new RuleTester({
+  parser: require.resolve('vue-eslint-parser'),
+  parserOptions: { ecmaVersion: 2015 }
+})
+tester.run('static-class-names-order', rule, {
+
+  valid: [
+    {
+      filename: 'no-classes.vue',
+      code: '<template><div></div></template>'
+    },
+    {
+      filename: 'one-class.vue',
+      code: '<template><div class="a"></div></template>'
+    },
+    {
+      filename: 'single-space.vue',
+      code: '<template><div class="a b c"></div></template>'
+    },
+    {
+      filename: 'multiple-spaces.vue',
+      code: '<template><div class="a       b       c"></div></template>'
+    },
+    {
+      filename: 'tabs.vue',
+      code: '<template><div class="a  b  c"></div></template>'
+    }
+  ],
+
+  invalid: [
+    {
+      filename: 'two-classes.vue',
+      code: '<template><div class="b a"></div></template>',
+      output: '<template><div class="a b"></div></template>',
+      errors: [{
+        message: 'Classes should be ordered alphabetically.',
+        type: 'VAttribute'
+      }]
+    },
+    {
+      filename: 'three-classes.vue',
+      code:
+        `<template>
+          <div class="c b a">
+          </div>
+        </template>`,
+      output:
+        `<template>
+          <div class="a b c">
+          </div>
+        </template>`,
+      errors: [
+        {
+          message: 'Classes should be ordered alphabetically.',
+          type: 'VAttribute'
+        }
+      ]
+    }
+  ]
+})