Fixed false positives in no-side-effects-in-computed-properties (#1027)

Author: ota-meshi

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

@@ -24,20 +24,38 @@ module.exports = {
 
   create (context) {
     const forbiddenNodes = []
+    let scopeStack = { upper: null, body: null }
+
+    function onFunctionEnter (node) {
+      scopeStack = { upper: scopeStack, body: node.body }
+    }
+
+    function onFunctionExit () {
+      scopeStack = scopeStack.upper
+    }
 
     return Object.assign({},
       {
+        ':function': onFunctionEnter,
+        ':function:exit': onFunctionExit,
+
         // this.xxx <=|+=|-=>
         'AssignmentExpression' (node) {
           if (node.left.type !== 'MemberExpression') return
           if (utils.parseMemberExpression(node.left)[0] === 'this') {
-            forbiddenNodes.push(node)
+            forbiddenNodes.push({
+              node,
+              targetBody: scopeStack.body
+            })
           }
         },
         // this.xxx <++|-->
         'UpdateExpression > MemberExpression' (node) {
           if (utils.parseMemberExpression(node)[0] === 'this') {
-            forbiddenNodes.push(node)
+            forbiddenNodes.push({
+              node,
+              targetBody: scopeStack.body
+            })
           }
         },
         // this.xxx.func()
@@ -46,19 +64,23 @@ module.exports = {
           const MUTATION_REGEX = /(this.)((?!(concat|slice|map|filter)\().)[^\)]*((push|pop|shift|unshift|reverse|splice|sort|copyWithin|fill)\()/g
 
           if (MUTATION_REGEX.test(code)) {
-            forbiddenNodes.push(node)
+            forbiddenNodes.push({
+              node,
+              targetBody: scopeStack.body
+            })
           }
         }
       },
       utils.executeOnVue(context, (obj) => {
         const computedProperties = utils.getComputedProperties(obj)
 
         computedProperties.forEach(cp => {
-          forbiddenNodes.forEach(node => {
+          forbiddenNodes.forEach(({ node, targetBody }) => {
             if (
               cp.value &&
               node.loc.start.line >= cp.value.loc.start.line &&
-              node.loc.end.line <= cp.value.loc.end.line
+              node.loc.end.line <= cp.value.loc.end.line &&
+              targetBody === cp.value
             ) {
               context.report({
                 node: node,

lib/utils/index.js

@@ -822,7 +822,7 @@ module.exports = {
         isFunc = true
       } else {
         if (n.computed) {
-          parsedCallee.push('[]')
+          parsedCallee.push('[]' + (isFunc ? '()' : ''))
         } else if (n.property.type === 'Identifier') {
           parsedCallee.push(n.property.name + (isFunc ? '()' : ''))
         }

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

@@ -143,6 +143,36 @@ ruleTester.run('no-side-effects-in-computed-properties', rule, {
         }
       })`,
       parserOptions
+    },
+    {
+      code: `Vue.component('test', {
+        computed: {
+          test () {
+            return {
+              action1() {
+                this.something++
+              },
+              action2() {
+                this.something = 1
+              },
+              action3() {
+                this.something.reverse()
+              }
+            }
+          },
+        }
+      })`,
+      parserOptions
+    },
+    {
+      code: `Vue.component('test', {
+        computed: {
+          test () {
+            return this.something['a']().reverse()
+          },
+        }
+      })`,
+      parserOptions
     }
   ],
   invalid: [