Merge 9e7a35f into caeb223

eslint · Jun 27, 2018 · b216347 · b216347
2 parents caeb223 + 9e7a35f
commit b216347
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Showing 2 changed files with 21 additions and 2 deletions.
diff --git a/lib/rules/prefer-const.js b/lib/rules/prefer-const.js
@@ -170,7 +170,7 @@ function getIdentifierIfShouldBeConst(variable, ignoreReadBeforeAssign) {
                     const elements = leftNode.elements;
 
                     hasOuterVariables = elements
-                        .map(element => element.name)
+                        .map(element => element && element.name)
                         .some(name => isOuterVariableInDestructing(name, variable.scope));
                 }
                 if (hasOuterVariables) {

diff --git a/tests/lib/rules/prefer-const.js b/tests/lib/rules/prefer-const.js
@@ -121,7 +121,11 @@ ruleTester.run("prefer-const", rule, {
         {
             code: "let x; function foo() { bar(x); } x = 0;",
             options: [{ ignoreReadBeforeAssign: true }]
-        }
+        },
+
+        // https://github.com/eslint/eslint/issues/10520
+        "const x = [1,2]; let y; [,y] = x; y = 0;",
+        "const x = [1,2,3]; let y, z; [y,,z] = x; y = 0; z = 0;"
     ],
     invalid: [
         {
@@ -361,6 +365,21 @@ ruleTester.run("prefer-const", rule, {
                 { message: "'foo' is never reassigned. Use 'const' instead.", type: "Identifier" },
                 { message: "'bar' is never reassigned. Use 'const' instead.", type: "Identifier" }
             ]
+        },
+
+        // https://github.com/eslint/eslint/issues/10520
+        {
+            code: "const x = [1,2]; let [,y] = x;",
+            output: "const x = [1,2]; const [,y] = x;",
+            errors: [{ message: "'y' is never reassigned. Use 'const' instead.", type: "Identifier" }]
+        },
+        {
+            code: "const x = [1,2,3]; let [y,,z] = x;",
+            output: "const x = [1,2,3]; const [y,,z] = x;",
+            errors: [
+                { message: "'y' is never reassigned. Use 'const' instead.", type: "Identifier" },
+                { message: "'z' is never reassigned. Use 'const' instead.", type: "Identifier" }
+            ]
         }
     ]
 });