[New] no-unused-modules: Support destructuring

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

Diff for: CHANGELOG.md

@@ -11,6 +11,7 @@ This change log adheres to standards from [Keep a CHANGELOG](http://keepachangel
 - [`no-internal-modules`]: Add `forbid` option ([#1846], thanks [@guillaumewuip])
 - add [`no-relative-packages`] ([#1860], [#966], thanks [@tapayne88] [@panrafal])
 - add [`no-import-module-exports`] rule: report import declarations with CommonJS exports ([#804], thanks [@kentcdodds] and [@ttmarek])
+- [`no-unused-modules`]: Support destructuring assignment for `export`. ([#1997], thanks [@s-h-a-d-o-w])
 
 ### Fixed
 - [`export`]/TypeScript: properly detect export specifiers as children of a TS module block ([#1889], thanks [@andreubotella])
@@ -760,6 +761,7 @@ for info on changes for earlier releases.
 
 [`memo-parser`]: ./memo-parser/README.md
 
+[#1997]: https://github.com/benmosher/eslint-plugin-import/pull/1997
 [#1993]: https://github.com/benmosher/eslint-plugin-import/pull/1993
 [#1983]: https://github.com/benmosher/eslint-plugin-import/pull/1983
 [#1974]: https://github.com/benmosher/eslint-plugin-import/pull/1974
@@ -1344,3 +1346,4 @@ for info on changes for earlier releases.
 [@christianvuerings]: https://github.com/christianvuerings
 [@devongovett]: https://github.com/devongovett
 [@dwardu]: https://github.com/dwardu
+[@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

@@ -970,3 +970,23 @@ 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: [],
+  });
+});