Check for duplicate named exports in exported destructuring assignments (#144)

* Check for duplicate named exports in exported destructuring assignments

* Refactor duplicate error reporting

* Remove unnecessary check

src/parser/statement.js

@@ -909,23 +909,19 @@ pp.checkExport = function (node, checkNames, isDefault) {
     // Check for duplicate exports
     if (isDefault) {
       // Default exports
-      this.checkDuplicateExports(node, "default", isDefault);
+      this.checkDuplicateExports(node, "default");
     } else if (node.specifiers && node.specifiers.length) {
       // Named exports
       for (let specifier of node.specifiers) {
-        const name = specifier.exported.name;
-        if (name === "default") isDefault = true;
-        this.checkDuplicateExports(specifier, name, isDefault);
+        this.checkDuplicateExports(specifier, specifier.exported.name);
       }
     } else if (node.declaration) {
       // Exported declarations
       if (node.declaration.type === "FunctionDeclaration" || node.declaration.type === "ClassDeclaration") {
-        this.checkDuplicateExports(node, node.declaration.id.name, isDefault);
+        this.checkDuplicateExports(node, node.declaration.id.name);
       } else if (node.declaration.type === "VariableDeclaration") {
         for (let declaration of node.declaration.declarations) {
-          if (declaration.id.name) {
-            this.checkDuplicateExports(declaration, declaration.id.name, isDefault);
-          }
+          this.checkDeclaration(declaration.id);
         }
       }
     }
@@ -940,15 +936,31 @@ pp.checkExport = function (node, checkNames, isDefault) {
   }
 };
 
-pp.checkDuplicateExports = function(node, name, isDefault) {
+pp.checkDeclaration = function(node) {
+  if (node.type === "ObjectPattern") {
+    for (let prop of node.properties) {
+      this.checkDeclaration(prop);
+    }
+  } else if (node.type === "ArrayPattern") {
+    for (let elem of node.elements) {
+      this.checkDeclaration(elem);
+    }
+  } else if (node.type === "ObjectProperty") {
+    this.checkDeclaration(node.value);
+  } else if (node.type === "Identifier") {
+    this.checkDuplicateExports(node, node.name);
+  }
+};
+
+pp.checkDuplicateExports = function(node, name) {
   if (this.state.exportedIdentifiers.indexOf(name) > -1) {
-    this.raiseDuplicateExportError(node, name, isDefault);
+    this.raiseDuplicateExportError(node, name);
   }
   this.state.exportedIdentifiers.push(name);
 };
 
-pp.raiseDuplicateExportError = function(node, name, isDefault) {
-  this.raise(node.start, isDefault ?
+pp.raiseDuplicateExportError = function(node, name) {
+  this.raise(node.start, name === "default" ?
     "Only one default export allowed per module." :
     `\`${name}\` has already been exported. Exported identifiers must be unique.`
   );

test/fixtures/es2015/modules/duplicate-named-export-destructuring/actual.js

@@ -1,2 +1,11 @@
-export const { rhythm } = typography;
-export const { TypographyStyle } = typography;
+export const { foo } = bar;
+export const { foo: foo2 } = bar;
+export const { foo: { baz } } = bar;
+export const { foo: { baz:  { qux } } } = bar;
+export const { foo: { baz:  { qux2 } }, foo3 } = bar;
+export const [foo4] = bar;
+export const [[baz2]] = bar;
+export const [{ foo: [baz3] }, { foo2: [baz4] }] = bar;
+export const { foo: { baz: { qux3 } }, foo2: { baz2: [qux4]} } = bar;
+export const { foo: { baz: { qux5 } }, foo2: { baz2: [{qux6}]} } = bar;
+export const { Foo } = bar;

test/fixtures/es2015/modules/duplicate-named-export-destructuring10/actual.js

@@ -0,0 +1,2 @@
+export function foo() {};
+export const { a: [{foo}] } = bar;

test/fixtures/es2015/modules/duplicate-named-export-destructuring10/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`foo` has already been exported. Exported identifiers must be unique. (2:20)"
+}

test/fixtures/es2015/modules/duplicate-named-export-destructuring11/actual.js

@@ -0,0 +1,2 @@
+export function foo4() {};
+export const [{ a: [{ foo }], b: { foo2: [{ foo3: foo4 }] } }] = bar;

test/fixtures/es2015/modules/duplicate-named-export-destructuring11/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`foo4` has already been exported. Exported identifiers must be unique. (2:50)"
+}

test/fixtures/es2015/modules/duplicate-named-export-destructuring12/actual.js

@@ -0,0 +1,2 @@
+export function foo4() {};
+export const { a: [{ foo }], b: { foo2: [{ foo3: foo4 }] } } = bar;

test/fixtures/es2015/modules/duplicate-named-export-destructuring12/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`foo4` has already been exported. Exported identifiers must be unique. (2:49)"
+}

test/fixtures/es2015/modules/duplicate-named-export-destructuring13/actual.js

@@ -0,0 +1,2 @@
+export function foo4() {};
+export const { a: [{ foo4: foo }], b, c: { foo2: [{ foo3: foo4 }] } } = bar;

test/fixtures/es2015/modules/duplicate-named-export-destructuring13/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`foo4` has already been exported. Exported identifiers must be unique. (2:58)"
+}

test/fixtures/es2015/modules/duplicate-named-export-destructuring14/actual.js

@@ -0,0 +1,3 @@
+export const foo = 1;
+export const { foo2: foo } = bar;
+

test/fixtures/es2015/modules/duplicate-named-export-destructuring14/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`foo` has already been exported. Exported identifiers must be unique. (2:21)"
+}

test/fixtures/es2015/modules/duplicate-named-export-destructuring15/actual.js

@@ -0,0 +1,3 @@
+export const { foo: foo2 } = bar;
+export const foo2 = 1;
+

test/fixtures/es2015/modules/duplicate-named-export-destructuring15/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`foo2` has already been exported. Exported identifiers must be unique. (2:13)"
+}

test/fixtures/es2015/modules/duplicate-named-export-destructuring2/actual.js

@@ -0,0 +1,2 @@
+export function foo() {};
+export const { foo } = bar;

test/fixtures/es2015/modules/duplicate-named-export-destructuring2/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`foo` has already been exported. Exported identifiers must be unique. (2:15)"
+}

test/fixtures/es2015/modules/duplicate-named-export-destructuring3/actual.js

@@ -0,0 +1,2 @@
+export const { foo } = bar;
+export function foo() {};

test/fixtures/es2015/modules/duplicate-named-export-destructuring3/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`foo` has already been exported. Exported identifiers must be unique. (2:0)"
+}

test/fixtures/es2015/modules/duplicate-named-export-destructuring4/actual.js

@@ -0,0 +1,2 @@
+export function foo() {};
+export const [foo] = bar;

test/fixtures/es2015/modules/duplicate-named-export-destructuring4/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`foo` has already been exported. Exported identifiers must be unique. (2:14)"
+}

test/fixtures/es2015/modules/duplicate-named-export-destructuring5/actual.js

@@ -0,0 +1,2 @@
+export const [foo] = bar;
+export function foo() {};

test/fixtures/es2015/modules/duplicate-named-export-destructuring5/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`foo` has already been exported. Exported identifiers must be unique. (2:0)"
+}

test/fixtures/es2015/modules/duplicate-named-export-destructuring6/actual.js

@@ -0,0 +1,2 @@
+export const { foo } = bar;
+export const [foo] = bar2;

test/fixtures/es2015/modules/duplicate-named-export-destructuring6/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`foo` has already been exported. Exported identifiers must be unique. (2:14)"
+}

test/fixtures/es2015/modules/duplicate-named-export-destructuring7/actual.js

@@ -0,0 +1,2 @@
+export const [foo] = bar;
+export const { foo } = bar2;

test/fixtures/es2015/modules/duplicate-named-export-destructuring7/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`foo` has already been exported. Exported identifiers must be unique. (2:15)"
+}

test/fixtures/es2015/modules/duplicate-named-export-destructuring8/actual.js

@@ -0,0 +1,2 @@
+export class Foo {};
+export const { Foo } = bar;

test/fixtures/es2015/modules/duplicate-named-export-destructuring8/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`Foo` has already been exported. Exported identifiers must be unique. (2:15)"
+}

test/fixtures/es2015/modules/duplicate-named-export-destructuring9/actual.js

@@ -0,0 +1,2 @@
+export class Foo {};
+export const [Foo] = bar;

test/fixtures/es2015/modules/duplicate-named-export-destructuring9/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "`Foo` has already been exported. Exported identifiers must be unique. (2:14)"
+}