[New] Add vue/singleline-html-element-content-newline rule

README.md

@@ -231,6 +231,7 @@ Enforce all the rules in this category, as well as all higher priority rules, wi
 |:---|:--------|:------------|
 | :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/script-indent](./docs/rules/script-indent.md) | enforce consistent indentation in `<script>` |
+| :wrench: | [vue/singleline-html-element-content-newline](./docs/rules/singleline-html-element-content-newline.md) | require a line break before and after the contents of a singleline element |
 
 ### Deprecated
 

docs/rules/singleline-html-element-content-newline.md

@@ -0,0 +1,102 @@
+# require a line break before and after the contents of a singleline element (vue/singleline-html-element-content-newline)
+
+- :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.
+
+## :book: Rule Details
+
+This rule enforces a line break before and after the contents of a singleline element.
+
+
+:-1: Examples of **incorrect** code:
+
+```html
+<div attr>content</div>
+
+<tr attr><td>{{ data1 }}</td><td>{{ data2 }}</td></tr>
+
+<div attr><!-- comment --></div>
+```
+
+:+1: Examples of **correct** code:
+
+```html
+<div attr>
+  content
+</div>
+
+<tr attr>
+  <td>
+    {{ data1 }}
+  </td>
+  <td>
+    {{ data2 }}
+  </td>
+</tr>
+
+<div attr>
+  <!-- comment -->
+</div>
+```
+
+## :wrench: Options
+
+```json
+{
+  "vue/singleline-html-element-content-newline": ["error", {
+    "strict": false,
+    "ignoreNames": ["pre", "textarea"]
+  }]
+}
+```
+
+- `strict` ... if false, if there are no attributes on the element, this rule allows having contents in one line.  
+    if true, even if there are no attributes on the element, this rule disallows having contents in one line.  
+    default `false`
+- `ignoreNames` ... the configuration for element names to ignore line breaks style.  
+    default `["pre", "textarea"]`
+
+:-1: Examples of **incorrect** code for `{strict: true}`:
+
+```html
+/* eslint vue/singleline-html-element-content-newline: ["error", { "strict": true}] */
+
+<div>content</div>
+
+<tr><td>{{ data1 }}</td><td>{{ data2 }}</td></tr>
+
+<div><!-- comment --></div>
+```
+
+:+1: Examples of **correct** code for `{strict: false}` (default):
+
+```html
+/* eslint vue/singleline-html-element-content-newline: ["error", { "strict": false}] */
+
+<div>content</div>
+
+<tr><td>{{ data1 }}</td><td>{{ data2 }}</td></tr>
+
+<div><!-- comment --></div>
+```
+
+:-1: Examples of **incorrect** code for `{strict: false}` (default):
+
+```html
+/* eslint vue/singleline-html-element-content-newline: ["error", { "strict": false}] */
+
+<div attr>content</div>
+
+<tr attr><td>{{ data1 }}</td><td>{{ data2 }}</td></tr>
+
+<div attr><!-- comment --></div>
+```
+
+:+1: Examples of **correct** code for `ignoreNames`:
+
+```html
+/* eslint vue/singleline-html-element-content-newline: ["error", { "ignoreNames": ["VueComponent", "pre", "textarea"]}] */
+
+<VueComponent>content</VueComponent>
+
+<VueComponent attr><span>content</span></VueComponent>
+```

lib/index.js

@@ -46,6 +46,7 @@ module.exports = {
     'require-valid-default-prop': require('./rules/require-valid-default-prop'),
     'return-in-computed-property': require('./rules/return-in-computed-property'),
     'script-indent': require('./rules/script-indent'),
+    'singleline-html-element-content-newline': require('./rules/singleline-html-element-content-newline'),
     'this-in-template': require('./rules/this-in-template'),
     'v-bind-style': require('./rules/v-bind-style'),
     'v-on-style': require('./rules/v-on-style'),

lib/rules/singleline-html-element-content-newline.js

@@ -0,0 +1,152 @@
+/**
+ * @author Yosuke Ota
+ * See LICENSE file in root directory for full license.
+ */
+'use strict'
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+const utils = require('../utils')
+
+// ------------------------------------------------------------------------------
+// Helpers
+// ------------------------------------------------------------------------------
+
+function isSinglelineElement (element) {
+  return element.loc.start.line === element.endTag.loc.start.line
+}
+
+function parseOptions (options) {
+  return Object.assign({
+    'ignoreNames': ['pre', 'textarea'],
+    'strict': false
+  }, options)
+}
+
+/**
+ * Check whether the given element is empty or not.
+ * This ignores whitespaces, doesn't ignore comments.
+ * @param {VElement} node The element node to check.
+ * @param {SourceCode} sourceCode The source code object of the current context.
+ * @returns {boolean} `true` if the element is empty.
+ */
+function isEmpty (node, sourceCode) {
+  const start = node.startTag.range[1]
+  const end = node.endTag.range[0]
+  return sourceCode.text.slice(start, end).trim() === ''
+}
+
+// ------------------------------------------------------------------------------
+// Rule Definition
+// ------------------------------------------------------------------------------
+
+module.exports = {
+  meta: {
+    docs: {
+      description: 'require a line break before and after the contents of a singleline element',
+      category: undefined,
+      url: 'https://github.com/vuejs/eslint-plugin-vue/blob/v5.0.0-beta.2/docs/rules/singleline-html-element-content-newline.md'
+    },
+    fixable: 'whitespace',
+    schema: [{
+      type: 'object',
+      properties: {
+        'strict': {
+          type: 'boolean'
+        },
+        'ignoreNames': {
+          type: 'array',
+          items: { type: 'string' },
+          uniqueItems: true,
+          additionalItems: false
+        }
+      },
+      additionalProperties: false
+    }],
+    messages: {
+      unexpectedAfterClosingBracket: `Expected 1 line break after closing bracket of the "{{name}}" element, but no line breaks found.`,
+      unexpectedBeforeOpeningBracket: `Expected 1 line break before opening bracket of the "{{name}}" element, but no line breaks found.`
+    }
+  },
+
+  create (context) {
+    const options = parseOptions(context.options[0])
+    const ignoreNames = options.ignoreNames
+    const strict = options.strict
+    const template = context.parserServices.getTemplateBodyTokenStore && context.parserServices.getTemplateBodyTokenStore()
+    const sourceCode = context.getSourceCode()
+
+    let inIgnoreElement
+
+    return utils.defineTemplateBodyVisitor(context, {
+      'VElement' (node) {
+        if (inIgnoreElement) {
+          return
+        }
+        if (ignoreNames.indexOf(node.name) >= 0) {
+          // ignore element name
+          inIgnoreElement = node
+          return
+        }
+        if (node.startTag.selfClosing || !node.endTag) {
+          // self closing
+          return
+        }
+
+        if (!isSinglelineElement(node)) {
+          return
+        }
+        if (!strict && node.startTag.attributes.length === 0) {
+          return
+        }
+
+        const getTokenOption = { includeComments: true, filter: (token) => token.type !== 'HTMLWhitespace' }
+        const contentFirst = template.getTokenAfter(node.startTag, getTokenOption)
+        const contentLast = template.getTokenBefore(node.endTag, getTokenOption)
+
+        context.report({
+          node: template.getLastToken(node.startTag),
+          loc: {
+            start: node.startTag.loc.end,
+            end: contentFirst.loc.start
+          },
+          messageId: 'unexpectedAfterClosingBracket',
+          data: {
+            name: node.name
+          },
+          fix (fixer) {
+            const range = [node.startTag.range[1], contentFirst.range[0]]
+            return fixer.replaceTextRange(range, '\n')
+          }
+        })
+
+        if (isEmpty(node, sourceCode)) {
+          return
+        }
+
+        context.report({
+          node: template.getFirstToken(node.endTag),
+          loc: {
+            start: contentLast.loc.end,
+            end: node.endTag.loc.start
+          },
+          messageId: 'unexpectedBeforeOpeningBracket',
+          data: {
+            name: node.name
+          },
+          fix (fixer) {
+            const range = [contentLast.range[1], node.endTag.range[0]]
+            return fixer.replaceTextRange(range, '\n')
+          }
+        })
+      },
+      'VElement:exit' (node) {
+        if (inIgnoreElement === node) {
+          inIgnoreElement = null
+        }
+      }
+    })
+  }
+}