Add component-data rule.

Author: armano2

docs/rules/component-data.md

@@ -0,0 +1,33 @@
+# Enforces that a component data must be a function (component-data)
+
+When using the data property on a component (i.e. anywhere except on `new Vue`), the value must be a function that returns an object.
+
+## :book: Rule Details
+
+When the value of `data` is an object, it’s shared across all instances of a component.
+
+:-1: Examples of **incorrect** code for this rule:
+
+```js
+Vue.component('some-comp', {
+  data: {
+    foo: 'bar'
+  }
+})
+```
+
+:+1: Examples of **correct** code for this rule:
+
+```js
+Vue.component('some-comp', {
+  data: function () {
+    return {
+      foo: 'bar'
+    }
+  }
+})
+```
+
+## :wrench: Options
+
+Nothing.

lib/rules/component-data.js

@@ -0,0 +1,57 @@
+/**
+ * @fileoverview When using the data property on a component (i.e. anywhere except on new Vue), the value must be a function that returns an object.
+ * @author Armano
+ */
+'use strict'
+
+const utils = require('../utils')
+
+function create (context) {
+  // variables should be defined here
+
+  // ----------------------------------------------------------------------
+  // Helpers
+  // ----------------------------------------------------------------------
+
+  // any helper functions should go here or else delete this section
+
+  // ----------------------------------------------------------------------
+  // Public
+  // ----------------------------------------------------------------------
+
+  return Object.assign({},
+    utils.executeOnVueComponent(context, (obj) => {
+      obj.properties
+        .filter(p =>
+          p.key.type === 'Identifier' &&
+          p.key.name === 'data' &&
+          p.value.type !== 'FunctionExpression'
+        ).forEach(cp => {
+          context.report({
+            node: cp.value,
+            message: 'Component `data` must be a function.'
+          })
+        })
+    })
+  )
+}
+
+// ------------------------------------------------------------------------------
+// Rule Definition
+// ------------------------------------------------------------------------------
+
+module.exports = {
+  meta: {
+    docs: {
+      description: 'Enforces that a component data must be a function',
+      category: 'Possible Errors',
+      recommended: false
+    },
+    fixable: null,  // or "code" or "whitespace"
+    schema: [
+      // fill in your schema
+    ]
+  },
+
+  create
+}

lib/rules/no-side-effects-in-computed-properties.js

@@ -33,7 +33,7 @@ function create (context) {
         }
       }
     },
-    utils.executeOnVueComponent(context, (obj) => {
+    utils.executeOnVue(context, (obj) => {
       const computedProperties = utils.getComputedProperties(obj)
 
       computedProperties.forEach(cp => {

lib/rules/order-in-components.js

@@ -80,7 +80,7 @@ function create (context) {
   const extendedOrder = order.map(property => groups[property] || property)
   const orderMap = getOrderMap(extendedOrder)
 
-  return utils.executeOnVueComponent(context, (obj) => {
+  return utils.executeOnVue(context, (obj) => {
     checkOrder(obj.properties, orderMap, context)
   })
 }

lib/utils/index.js

@@ -363,6 +363,25 @@ module.exports = {
       node.arguments[0].type === 'ObjectExpression'
   },
 
+  executeOnVue (context, cb) {
+    return Object.assign(
+      this.executeOnVueComponent(context, cb),
+      this.executeOnVueInstance(context, cb)
+    )
+  },
+
+  executeOnVueInstance (context, cb) {
+    const _this = this
+
+    return {
+      'NewExpression:exit' (node) {
+        // new Vue({})
+        if (!_this.isVueInstance(node)) return
+        cb(node.arguments[0])
+      }
+    }
+  },
+
   executeOnVueComponent (context, cb) {
     const filePath = context.getFilename()
     const _this = this
@@ -377,11 +396,6 @@ module.exports = {
         // Vue.component('xxx', {}) || component('xxx', {})
         if (!_this.isVueComponent(node)) return
         cb(node.arguments.slice(-1)[0])
-      },
-      'NewExpression:exit' (node) {
-        // new Vue({})
-        if (!_this.isVueInstance(node)) return
-        cb(node.arguments[0])
       }
     }
   }

tests/lib/rules/component-data.js

@@ -0,0 +1,105 @@
+/**
+ * @fileoverview When using the data property on a component (i.e. anywhere except on new Vue), the value must be a function that returns an object.
+ * @author Armano
+ */
+'use strict'
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+var rule = require('../../../lib/rules/component-data')
+
+const RuleTester = require('eslint').RuleTester
+
+// ------------------------------------------------------------------------------
+// Tests
+// ------------------------------------------------------------------------------
+
+var ruleTester = new RuleTester()
+ruleTester.run('component-data', rule, {
+
+  valid: [
+    {
+      filename: 'test.js',
+      code: `
+        new Vue({
+          data: function () {
+            return {
+              foo: 'bar'
+            }
+          }
+        })
+      `
+    },
+    {
+      filename: 'test.js',
+      code: `
+        new Vue({
+          data: {
+            foo: 'bar'
+          }
+        })
+      `
+    },
+    {
+      filename: 'test.js',
+      code: `
+        Vue.component('some-comp', {
+          data: function () {
+            return {
+              foo: 'bar'
+            }
+          }
+        })
+      `,
+      parserOptions: { ecmaVersion: 6 }
+    },
+    {
+      filename: 'test.vue',
+      code: `
+        export default {
+          data: function () {
+            return {
+              foo: 'bar'
+            }
+          }
+        }
+      `,
+      parserOptions: { ecmaVersion: 6, sourceType: 'module' }
+    }
+  ],
+
+  invalid: [
+    {
+      filename: 'test.js',
+      code: `
+        Vue.component('some-comp', {
+          data: {
+            foo: 'bar'
+          }
+        })
+      `,
+      parserOptions: { ecmaVersion: 6 },
+      errors: [{
+        message: 'Component `data` must be a function.',
+        line: 3
+      }]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+        export default {
+          data: {
+            foo: 'bar'
+          }
+        }
+      `,
+      parserOptions: { ecmaVersion: 6, sourceType: 'module' },
+      errors: [{
+        message: 'Component `data` must be a function.',
+        line: 3
+      }]
+    }
+  ]
+})