[Fix] no-unused-modules: Support destructuring

Author: s-h-a-d-o-w

Diff for: CHANGELOG.md

@@ -25,6 +25,7 @@ This change log adheres to standards from [Keep a CHANGELOG](http://keepachangel
 - [`extensions`]/[`no-cycle`]/[`no-extraneous-dependencies`]: Correct module real path resolution ([#1696], thanks [@paztis])
 - [`no-named-default`]: ignore Flow import type and typeof ([#1983], thanks [@christianvuerings])
 - [`no-extraneous-dependencies`]: Exclude flow `typeof` imports ([#1534], thanks [@devongovett])
+- [`no-unused-modules`]: Support destructuring assignment for `export`. ([#1997], thanks [@s-h-a-d-o-w])
 
 ### Changed
 - [Generic Import Callback] Make callback for all imports once in rules ([#1237], thanks [@ljqx])
@@ -759,6 +760,7 @@ for info on changes for earlier releases.
 
 [`memo-parser`]: ./memo-parser/README.md
 
+[#1997]: https://github.com/benmosher/eslint-plugin-import/pull/1997
 [#1983]: https://github.com/benmosher/eslint-plugin-import/pull/1983
 [#1974]: https://github.com/benmosher/eslint-plugin-import/pull/1974
 [#1958]: https://github.com/benmosher/eslint-plugin-import/pull/1958
@@ -1340,4 +1342,5 @@ for info on changes for earlier releases.
 [@panrafal]: https://github.com/panrafal
 [@ttmarek]: https://github.com/ttmarek
 [@christianvuerings]: https://github.com/christianvuerings
-[@devongovett]: https://github.com/devongovett
+[@devongovett]: https://github.com/devongovett
+[@s-h-a-d-o-w]: https://github.com/s-h-a-d-o-w

Diff for: src/rules/no-unused-modules.js

@@ -4,7 +4,7 @@
  * @author René Fermann
  */
 
-import Exports from '../ExportMap';
+import Exports, { recursivePatternCapture } from '../ExportMap';
 import { getFileExtensions } from 'eslint-module-utils/ignore';
 import resolve from 'eslint-module-utils/resolve';
 import docsUrl from '../docsUrl';
@@ -63,6 +63,8 @@ const IMPORT_DEFAULT_SPECIFIER = 'ImportDefaultSpecifier';
 const VARIABLE_DECLARATION = 'VariableDeclaration';
 const FUNCTION_DECLARATION = 'FunctionDeclaration';
 const CLASS_DECLARATION = 'ClassDeclaration';
+const IDENTIFIER = 'Identifier';
+const OBJECT_PATTERN = 'ObjectPattern';
 const TS_INTERFACE_DECLARATION = 'TSInterfaceDeclaration';
 const TS_TYPE_ALIAS_DECLARATION = 'TSTypeAliasDeclaration';
 const TS_ENUM_DECLARATION = 'TSEnumDeclaration';
@@ -80,7 +82,15 @@ function forEachDeclarationIdentifier(declaration, cb) {
       cb(declaration.id.name);
     } else if (declaration.type === VARIABLE_DECLARATION) {
       declaration.declarations.forEach(({ id }) => {
-        cb(id.name);
+        if(id.type === OBJECT_PATTERN) {
+          recursivePatternCapture(id, (pattern) => {
+            if (pattern.type === IDENTIFIER) {
+              cb(pattern.name);
+            }
+          });
+        } else {
+          cb(id.name);
+        }
       });
     }
   }

Diff for: tests/files/no-unused-modules/destructuring-a.js

@@ -0,0 +1 @@
+import {a, b} from "./destructuring-b";

Diff for: tests/files/no-unused-modules/destructuring-b.js

@@ -0,0 +1,2 @@
+const obj = {a: 1, dummy: {b: 2}};
+export const {a, dummy: {b}} = obj;

Diff for: tests/src/rules/no-unused-modules.js

@@ -965,3 +965,23 @@ describe('ignore flow types', () => {
     invalid: [],
   });
 });
+
+describe('support (nested) destructuring assignment', () => {
+  ruleTester.run('no-unused-modules', rule, {
+    valid: [
+      test({
+        options: unusedExportsOptions,
+        code: 'import {a, b} from "./destructuring-b";',
+        parser: require.resolve('babel-eslint'),
+        filename: testFilePath('./no-unused-modules/destructuring-a.js'),
+      }),
+      test({
+        options: unusedExportsOptions,
+        code: 'const obj = {a: 1, dummy: {b: 2}}; export const {a, dummy: {b}} = obj;',
+        parser: require.resolve('babel-eslint'),
+        filename: testFilePath('./no-unused-modules/destructuring-b.js'),
+      }),
+    ],
+    invalid: [],
+  });
+});