Add prefer-true-attribute-shorthand rule

docs/rules/README.md

@@ -353,6 +353,7 @@ For example:
 | [vue/no-v-text](./no-v-text.md) | disallow use of v-text |  |
 | [vue/padding-line-between-blocks](./padding-line-between-blocks.md) | require or disallow padding lines between blocks | :wrench: |
 | [vue/prefer-separate-static-class](./prefer-separate-static-class.md) | require static class names in template to be in a separate `class` attribute | :wrench: |
+| [vue/prefer-true-attribute-shorthand](./prefer-true-attribute-shorthand.md) | require shorthand form attribute when `v-bind` value is `true`. | :bulb: |
 | [vue/require-direct-export](./require-direct-export.md) | require the component to be directly exported |  |
 | [vue/require-emit-validator](./require-emit-validator.md) | require type definitions in emits | :bulb: |
 | [vue/require-expose](./require-expose.md) | require declare public properties using `expose` | :bulb: |

docs/rules/prefer-true-attribute-shorthand.md

@@ -0,0 +1,68 @@
+---
+pageClass: rule-details
+sidebarDepth: 0
+title: vue/prefer-true-attribute-shorthand
+description: require shorthand form attribute when `v-bind` value is `true`.
+---
+# vue/prefer-true-attribute-shorthand
+
+> require shorthand form attribute when `v-bind` value is `true`.
+
+- :exclamation: <badge text="This rule has not been released yet." vertical="middle" type="error"> ***This rule has not been released yet.*** </badge>
+- :bulb: Some problems reported by this rule are manually fixable by editor [suggestions](https://eslint.org/docs/developer-guide/working-with-rules#providing-suggestions).
+
+## :book: Rule Details
+
+`v-bind` attribute with `true` value usually can be written in shorthand form. This can reduce verbosity.
+
+<eslint-code-block :rules="{'vue/prefer-true-attribute-shorthand': ['error']}">
+
+```vue
+<template>
+  <!-- ✗ BAD -->
+  <MyComponent v-bind:show="true" />
+  <MyComponent :show="true" />
+
+  <!-- ✓ GOOD -->
+  <MyComponent show />
+  <MyComponent another-prop="true" />
+</template>
+```
+
+</eslint-code-block>
+
+However, those two representations are not always equivalent.
+This case will be occurred if the definition of a prop includes `String`:
+
+```vue
+<template>
+  <pre>{{ prop }}</pre>
+</template>
+
+<script>
+export default {
+  name: 'MyComponent',
+  props: {
+    prop: [String, Boolean]
+  }
+}
+</script>
+```
+
+```vue
+<template>
+  <MyComponent prop />
+  <MyComponent :prop="true"/>
+</template>
+```
+
+Those two calls will introduce different render result. See [this demo](https://sfc.vuejs.org/#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).
+
+## :wrench: Options
+
+Nothing.
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/vuejs/eslint-plugin-vue/blob/master/lib/rules/prefer-true-attribute-shorthand.js)
+- [Test source](https://github.com/vuejs/eslint-plugin-vue/blob/master/tests/lib/rules/prefer-true-attribute-shorthand.js)

lib/index.js

@@ -159,6 +159,7 @@ module.exports = {
     'padding-line-between-blocks': require('./rules/padding-line-between-blocks'),
     'prefer-separate-static-class': require('./rules/prefer-separate-static-class'),
     'prefer-template': require('./rules/prefer-template'),
+    'prefer-true-attribute-shorthand': require('./rules/prefer-true-attribute-shorthand'),
     'prop-name-casing': require('./rules/prop-name-casing'),
     'quote-props': require('./rules/quote-props'),
     'require-component-is': require('./rules/require-component-is'),

lib/rules/prefer-true-attribute-shorthand.js

@@ -0,0 +1,69 @@
+/**
+ * @author Pig Fang
+ * See LICENSE file in root directory for full license.
+ */
+'use strict'
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+const utils = require('../utils')
+
+// ------------------------------------------------------------------------------
+// Rule Definition
+// ------------------------------------------------------------------------------
+
+module.exports = {
+  meta: {
+    type: 'problem',
+    docs: {
+      description:
+        'require shorthand form attribute when `v-bind` value is `true`.',
+      categories: undefined,
+      url: 'https://eslint.vuejs.org/rules/prefer-true-attribute-shorthand.html'
+    },
+    fixable: null,
+    hasSuggestions: true,
+    schema: [],
+    messages: {
+      report:
+        "Boolean prop with 'true' value can be written in shorthand form.",
+      fix: 'Rewrite this prop into shorthand form.'
+    }
+  },
+  /** @param {RuleContext} context */
+  create(context) {
+    // ...
+
+    return utils.defineTemplateBodyVisitor(context, {
+      /** @param {VDirective} node */
+      "VAttribute[directive=true][key.name.name='bind']"(node) {
+        const { argument } = node.key
+        if (
+          !argument ||
+          !node.value ||
+          !node.value.expression ||
+          node.value.expression.type !== 'Literal' ||
+          node.value.expression.value !== true
+        ) {
+          return
+        }
+
+        context.report({
+          node,
+          messageId: 'report',
+          suggest: [
+            {
+              messageId: 'fix',
+              fix: (fixer) => {
+                const sourceCode = context.getSourceCode()
+                return fixer.replaceText(node, sourceCode.getText(argument))
+              }
+            }
+          ]
+        })
+      }
+    })
+  }
+}

tests/lib/rules/prefer-true-attribute-shorthand.js

@@ -0,0 +1,133 @@
+/**
+ * @author Pig Fang
+ * See LICENSE file in root directory for full license.
+ */
+'use strict'
+
+const RuleTester = require('eslint').RuleTester
+const rule = require('../../../lib/rules/prefer-true-attribute-shorthand')
+
+const tester = new RuleTester({
+  parser: require.resolve('vue-eslint-parser'),
+  parserOptions: {
+    ecmaVersion: 2020,
+    sourceType: 'module'
+  }
+})
+
+tester.run('prefer-true-attribute-shorthand', rule, {
+  valid: [
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <MyComp v-if="true" />
+      </template>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <MyComp v-bind="true" />
+      </template>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <MyComp v-loading="true" />
+      </template>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <MyComp show="true" />
+      </template>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <MyComp v-bind:show="value" />
+      </template>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <MyComp :show="value" />
+      </template>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <MyComp v-bind:show="false" />
+      </template>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <MyComp :show="false" />
+      </template>
+      `
+    }
+  ],
+  invalid: [
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <MyComp v-bind:show="true" />
+      </template>`,
+      errors: [
+        {
+          messageId: 'report',
+          line: 3,
+          column: 17,
+          suggestions: [
+            {
+              messageId: 'fix',
+              output: `
+      <template>
+        <MyComp show />
+      </template>`
+            }
+          ]
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <MyComp :show="true" />
+      </template>`,
+      errors: [
+        {
+          messageId: 'report',
+          line: 3,
+          column: 17,
+          suggestions: [
+            {
+              messageId: 'fix',
+              output: `
+      <template>
+        <MyComp show />
+      </template>`
+            }
+          ]
+        }
+      ]
+    }
+  ]
+})