feat: add no-timing-in-fetch-data

docs/rules/no-timing-in-fetch-data.md

@@ -0,0 +1,50 @@
+# nuxt/no-timing-in-fetch-data
+
+> disallow `setTimeout/setInterval` in `asyncData/fetch`
+
+- :gear: This rule is included in `"plugin:nuxt/recommended"`.
+
+## Rule Details
+
+This rule is for preventing using `setTimeout/setInterval` in `asyncData/fetch` since it may lead to memory leak
+
+Examples of **incorrect** code for this rule:
+
+```js
+
+export default {
+  async asyncData() {
+    let foo = 'baz'
+  },
+  fetch() {
+    let foo = 'baz'
+  }
+}
+
+```
+
+Examples of **correct** code for this rule:
+
+```js
+
+export default {
+  asyncData() {
+    let foo = 'bar'
+    setTimeout(() => {
+      foo = 'baz'
+    }, 0)
+  },
+  fetch() {
+    let foo = 'bar'
+    setInterval(() => {
+      foo = 'baz'
+    }, 0)
+  }
+}
+
+```
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/nuxt/eslint-plugin-nuxt/blob/master/lib/rules/no-timing-in-fetch-data.js)
+- [Test source](https://github.com/nuxt/eslint-plugin-nuxt/blob/master/lib/rules/__test__/no-timing-in-fetch-data.test.js)

lib/configs/ssr.js

@@ -1,6 +1,7 @@
 module.exports = {
   extends: require.resolve('./base.js'),
   rules: {
-    'nuxt/no-globals-in-created': 'warn'
+    'nuxt/no-globals-in-created': 'warn',
+    'nuxt/no-timing-in-fetch-data': 'warn'
   }
 }

lib/index.js

@@ -4,7 +4,8 @@ module.exports = {
     'no-this-in-fetch': require('./rules/no-this-in-fetch')
   },
   configs: {
-    'base': require('./configs/base')
+    'base': require('./configs/base'),
+    'ssr': require('./configs/ssr')
   },
   processors: {
     '.vue': require('./processors')

lib/rules/__test__/no-timing-in-fetch-data.test.js

@@ -0,0 +1,94 @@
+/**
+ * @fileoverview disallow `setTimeout/setInterval` in `asyncData/fetch`
+ * @author Xin Du <[email protected]>
+ */
+'use strict'
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+var rule = require('../no-timing-in-fetch-data')
+
+var RuleTester = require('eslint').RuleTester
+
+const parserOptions = {
+  ecmaVersion: 2018,
+  sourceType: 'module'
+}
+
+// ------------------------------------------------------------------------------
+// Tests
+// ------------------------------------------------------------------------------
+
+var ruleTester = new RuleTester()
+ruleTester.run('no-timing-in-fetch-data', rule, {
+
+  valid: [
+    {
+      filename: 'test.vue',
+      code: `
+        export default {
+          async asyncData() {
+            let foo = 'baz'
+          },
+          fetch() {
+            let foo = 'baz'
+          }
+        }
+      `,
+      parserOptions
+    }
+  ],
+
+  invalid: [
+    {
+      filename: 'test.vue',
+      code: `
+        export default {
+          asyncData() {
+            let foo = 'bar'
+            setTimeout(() => {
+              foo = 'baz'
+            }, 0)
+          },
+          fetch() {
+            let foo = 'bar'
+            setInterval(() => {
+              foo = 'baz'
+            }, 0)
+          }
+        }
+      `,
+      errors: [{
+        message: 'Unexpected setTimeout in asyncData.',
+        type: 'CallExpression'
+      }, {
+        message: 'Unexpected setInterval in fetch.',
+        type: 'CallExpression'
+      }],
+      parserOptions
+    },
+    {
+      filename: 'test.vue',
+      code: `
+        export default {
+          asyncData() {
+            let timer = setInterval
+          },
+          fetch() {
+            let timer = setTimeout
+          }
+        }
+      `,
+      errors: [{
+        message: 'Unexpected setInterval in asyncData.',
+        type: 'VariableDeclarator'
+      }, {
+        message: 'Unexpected setTimeout in fetch.',
+        type: 'VariableDeclarator'
+      }],
+      parserOptions
+    }
+  ]
+})

lib/rules/no-timing-in-fetch-data.js

@@ -0,0 +1,70 @@
+/**
+ * @fileoverview disallow `setTimeout/setInterval` in `asyncData/fetch`
+ * @author Xin Du <[email protected]>
+ */
+'use strict'
+
+const utils = require('../utils')
+
+// ------------------------------------------------------------------------------
+// Rule Definition
+// ------------------------------------------------------------------------------
+
+module.exports = {
+  meta: {
+    docs: {
+      description: 'disallow `setTimeout/setInterval` in `asyncData/fetch`',
+      category: 'ssr'
+    },
+    messages: {
+      noTiming: 'Unexpected {{name}} in {{funcName}}.'
+    }
+  },
+
+  create: function (context) {
+    const forbiddenNodes = []
+    const options = context.options[0] || {}
+
+    const HOOKS = new Set(
+      ['fetch', 'asyncData'].concat(options.methods || [])
+    )
+    const TIMING = ['setTimeout', 'setInterval']
+
+    function isTiming (name) {
+      return TIMING.includes(name)
+    }
+
+    return {
+      CallExpression: function (node) {
+        if (!node.callee) return
+
+        const name = node.callee.name
+
+        if (isTiming(name)) {
+          forbiddenNodes.push({ name, node })
+        }
+      },
+      VariableDeclarator (node) {
+        if (!node.init) return
+
+        const name = node.init.name
+
+        if (isTiming(name)) {
+          forbiddenNodes.push({ name, node })
+        }
+      },
+      ...utils.executeOnVue(context, obj => {
+        for (const { funcName, name, node } of utils.getFunctionWithChild(obj, HOOKS, forbiddenNodes)) {
+          context.report({
+            node,
+            messageId: 'noTiming',
+            data: {
+              name,
+              funcName
+            }
+          })
+        }
+      })
+    }
+  }
+}