fix prefer-lodash-typecheck to warn on undefined checks of declared v…

…ariables (fixes #21)
captbaritone · Oct 9, 2016 · 8ee071a · 8ee071a
1 parent ef228f0
commit 8ee071a
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Showing 2 changed files with 10 additions and 1 deletion.
diff --git a/src/rules/prefer-lodash-typecheck.js b/src/rules/prefer-lodash-typecheck.js
@@ -12,6 +12,7 @@
 
 module.exports = {
     create(context) {
+        const some = require('lodash/some')
         const {getIsTypeMethod} = require('../util/lodashUtil')
 
         const otherSides = {
@@ -27,9 +28,14 @@ module.exports = {
             return node.operator === '===' || node.operator === '!=='
         }
 
+        function isDeclaredVariable(node) {
+            const definedVariables = context.getScope().variables
+            return some(definedVariables, {name: node.name})
+        }
+
         function getValueForSide(node, side) {
             const otherSide = otherSides[side]
-            if (isTypeOf(node[side]) && (node[otherSide].value !== 'undefined' || node[side].argument.type !== 'Identifier')) {
+            if (isTypeOf(node[side]) && (node[otherSide].value !== 'undefined' || node[side].argument.type !== 'Identifier' || isDeclaredVariable(node[side].argument))) {
                 return node[otherSide].value
             }
         }

diff --git a/tests/lib/rules/prefer-lodash-typecheck.js b/tests/lib/rules/prefer-lodash-typecheck.js
@@ -36,5 +36,8 @@ ruleTester.run('prefer-lodash-typecheck', rule, {
     }, {
         code: 'var x = typeof a.b === "undefined"',
         errors: errors.undefined
+    }, {
+        code: 'var y; var x = typeof y === "undefined"',
+        errors: errors.undefined
     }]
 })