[New] no-anonymous-default-export: add allowNew option

Author: DamienCassou

Diff for: CHANGELOG.md

@@ -10,6 +10,7 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 - [`newline-after-import`]: add `considerComments` option ([#2399], thanks [@pri1311])
 - [`no-cycle`]: add `allowUnsafeDynamicCyclicDependency` option ([#2387], thanks [@GerkinDev])
 - [`no-restricted-paths`]: support arrays for `from` and `target` options ([#2466], thanks [@AdriAt360])
+- [`no-anonymous-default-export`]: add `allowNew` option ([#2505], thanks [@DamienCassou])
 
 ### Fixed
 - [`order`]: move nested imports closer to main import entry ([#2396], thanks [@pri1311])
@@ -1534,6 +1535,7 @@ for info on changes for earlier releases.
 [@chrislloyd]: https://github.com/chrislloyd
 [@christianvuerings]: https://github.com/christianvuerings
 [@christophercurrie]: https://github.com/christophercurrie
+[@DamienCassou]: https://github.com/DamienCassou
 [@danny-andrews]: https://github.com/dany-andrews
 [@darkartur]: https://github.com/darkartur
 [@davidbonnet]: https://github.com/davidbonnet

Diff for: docs/rules/no-anonymous-default-export.md

@@ -17,6 +17,7 @@ The complete default configuration looks like this.
   "allowAnonymousClass": false,
   "allowAnonymousFunction": false,
   "allowCallExpression": true, // The true value here is for backward compatibility
+  "allowNew": false,
   "allowLiteral": false,
   "allowObject": false
 }]
@@ -40,6 +41,8 @@ export default foo(bar)
 export default 123
 
 export default {}
+
+export default new Foo()
 ```
 
 ### Pass
@@ -70,4 +73,7 @@ export default 123
 
 /* eslint import/no-anonymous-default-export: [2, {"allowObject": true}] */
 export default {}
+
+/* eslint import/no-anonymous-default-export: [2, {"allowNew": true}] */
+export default new Foo()
 ```

Diff for: src/rules/no-anonymous-default-export.js

@@ -50,6 +50,11 @@ const defs = {
     description: 'If `false`, will report default export of a literal',
     message: 'Assign literal to a variable before exporting as module default',
   },
+  NewExpression: {
+    option: 'allowNew',
+    description: 'If `false`, will report default export of a class instantiation',
+    message: 'Assign instance to a variable before exporting as module default',
+  },
 };
 
 const schemaProperties = Object.keys(defs)

Diff for: tests/src/rules/no-anonymous-default-export.js

@@ -22,6 +22,7 @@ ruleTester.run('no-anonymous-default-export', rule, {
     test({ code: 'export default `foo`', options: [{ allowLiteral: true }] }),
     test({ code: 'export default {}', options: [{ allowObject: true }] }),
     test({ code: 'export default foo(bar)', options: [{ allowCallExpression: true }] }),
+    test({ code: 'export default new Foo()', options: [{ allowNew: true }] }),
 
     // Allow forbidden types with multiple options
     test({ code: 'export default 123', options: [{ allowLiteral: true, allowObject: true }] }),
@@ -53,6 +54,7 @@ ruleTester.run('no-anonymous-default-export', rule, {
     test({ code: 'export default `foo`', errors: [{ message: 'Assign literal to a variable before exporting as module default' }] }),
     test({ code: 'export default {}', errors: [{ message: 'Assign object to a variable before exporting as module default' }] }),
     test({ code: 'export default foo(bar)', options: [{ allowCallExpression: false }], errors: [{ message: 'Assign call result to a variable before exporting as module default' }] }),
+    test({ code: 'export default new Foo()', errors: [{ message: 'Assign instance to a variable before exporting as module default' }] }),
 
     // Test failure with non-covering exception
     test({ code: 'export default 123', options: [{ allowObject: true }], errors: [{ message: 'Assign literal to a variable before exporting as module default' }] }),