Fix: handle array-destructuring with obj assignment in prefer const

(fixes eslint#8308)
VictorHom · Sep 23, 2017 · 08616bf · 08616bf
1 parent a7668c2
commit 08616bf
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Showing 2 changed files with 37 additions and 10 deletions.
diff --git a/lib/rules/prefer-const.js b/lib/rules/prefer-const.js
@@ -199,6 +199,17 @@ function groupByDestructuring(variables, ignoreReadBeforeAssign) {
         }
     }
 
+    for (const key of identifierMap.keys()) {
+        const destructureGroup = identifierMap.get(key);
+        const destructureElement = destructureGroup[0];
+
+        if (destructureElement && destructureElement.parent && destructureElement.parent.elements) {
+            if (destructureElement.parent.elements.length !== destructureGroup.length) {
+                identifierMap.delete(key);
+            }
+        }
+    }
+
     return identifierMap;
 }
 

diff --git a/tests/lib/rules/prefer-const.js b/tests/lib/rules/prefer-const.js
@@ -56,16 +56,24 @@ ruleTester.run("prefer-const", rule, {
         "let a; function foo() { if (a) {} a = bar(); }",
         "let a; function foo() { a = a || bar(); baz(a); }",
         "let a; function foo() { bar(++a); }",
-        [
-            "let id;",
-            "function foo() {",
-            "    if (typeof id !== 'undefined') {",
-            "        return;",
-            "    }",
-            "    id = setInterval(() => {}, 250);",
-            "}",
-            "foo();"
-        ].join("\n"),
+        "let predicate; [typeNode.returnType, predicate] = foo();",
+        "let predicate; let rest; [typeNode.returnType, predicate, ...rest] = foo();",
+        {
+            code: "let predicate; [typeNode.returnType, predicate] = foo();",
+            options: [{ destructuring: "all" }]
+        },
+        {
+            code: [
+                "let id;",
+                "function foo() {",
+                "    if (typeof id !== 'undefined') {",
+                "        return;",
+                "    }",
+                "    id = setInterval(() => {}, 250);",
+                "}",
+                "foo();"
+            ].join("\n")
+        },
         "/*exported a*/ let a; function init() { a = foo(); }",
         "/*exported a*/ let a = 1",
         "let a; if (true) a = 0; foo(a);",
@@ -268,6 +276,14 @@ ruleTester.run("prefer-const", rule, {
                 { message: "'a' is never reassigned. Use 'const' instead.", type: "Identifier" }
             ]
         },
+        {
+            code: "let [ foo, bar ] = baz();",
+            output: "const [ foo, bar ] = baz();",
+            errors: [
+                { message: "'foo' is never reassigned. Use 'const' instead.", type: "Identifier" },
+                { message: "'bar' is never reassigned. Use 'const' instead.", type: "Identifier" }
+            ]
+        },
         {
             code: "let {a} = obj",
             output: "const {a} = obj",