feat(eslint-plugin): [no-invalid-void-type] better report message for void used as a constituent inside a function return type

packages/eslint-plugin/src/rules/no-invalid-void-type.ts

@@ -4,14 +4,17 @@ import * as util from '../util';
 interface Options {
   allowInGenericTypeArguments?: boolean | string[];
   allowAsThisParameter?: boolean;
+  allowUnionType?: boolean;
+  invalidUnionParameter?: boolean | string[];
 }
 
 type MessageIds =
   | 'invalidVoidForGeneric'
   | 'invalidVoidNotReturnOrGeneric'
   | 'invalidVoidNotReturn'
   | 'invalidVoidNotReturnOrThisParam'
-  | 'invalidVoidNotReturnOrThisParamOrGeneric';
+  | 'invalidVoidNotReturnOrThisParamOrGeneric'
+  | 'InvalidVoidForUnion';
 
 export default util.createRule<[Options], MessageIds>({
   name: 'no-invalid-void-type',
@@ -31,6 +34,8 @@ export default util.createRule<[Options], MessageIds>({
         'void is only valid as return type or type of `this` parameter.',
       invalidVoidNotReturnOrThisParamOrGeneric:
         'void is only valid as a return type or generic type variable or the type of a `this` parameter.',
+      InvalidVoidForUnion:
+        'void is not valid as a type constituent in a return type.',
     },
     schema: [
       {
@@ -49,15 +54,33 @@ export default util.createRule<[Options], MessageIds>({
           allowAsThisParameter: {
             type: 'boolean',
           },
+          invalidUnionParameter: {
+            oneOf: [
+              { type: 'boolean' },
+              {
+                type: 'array',
+                items: { type: 'string' },
+                minLength: 1,
+              },
+            ],
+          },
+          allowUnionType: {
+            type: 'boolean',
+          },
         },
         additionalProperties: false,
       },
     ],
   },
   defaultOptions: [
-    { allowInGenericTypeArguments: true, allowAsThisParameter: false },
+    {
+      allowInGenericTypeArguments: true,
+      allowAsThisParameter: false,
+      invalidUnionParameter: true,
+      allowUnionType:true,
+    },
   ],
-  create(context, [{ allowInGenericTypeArguments, allowAsThisParameter }]) {
+  create(context, [{ allowInGenericTypeArguments, allowAsThisParameter, invalidUnionParameter,allowUnionType }]) {
     const validParents: AST_NODE_TYPES[] = [
       AST_NODE_TYPES.TSTypeAnnotation, //
     ];
@@ -123,6 +146,15 @@ export default util.createRule<[Options], MessageIds>({
           node,
         });
       }
+
+      if (!invalidUnionParameter) {
+        context.report({
+          messageId: invalidUnionParameter
+            ? 'InvalidVoidForUnion'
+            : 'InvalidVoidForUnion',
+          node,
+        });
+      }
     }
 
     /**
@@ -188,7 +220,7 @@ export default util.createRule<[Options], MessageIds>({
 
         context.report({
           messageId:
-            allowInGenericTypeArguments && allowAsThisParameter
+            allowInGenericTypeArguments && allowAsThisParameter && allowUnionType
               ? 'invalidVoidNotReturnOrThisParamOrGeneric'
               : allowInGenericTypeArguments
               ? 'invalidVoidNotReturnOrGeneric'

packages/eslint-plugin/tests/rules/no-invalid-void-type.test.ts

@@ -98,6 +98,28 @@ function foo(): void | never {
   ],
 });
 
+ruleTester.run('invalidUnionParameter:true', rule, {
+  valid: [
+    {
+      code: 'type allowUnion = string | number',
+      options: [{ allowUnionType: true }],
+    },
+  ],
+  invalid: [
+    {
+      code: 'type invalidVoidUnion = void | number;',
+      options: [{ invalidUnionParameter: false }],
+      errors: [
+        {
+          messageId: 'InvalidVoidForUnion',
+          line: 1,
+          column: 25,
+        },
+      ],
+    },
+  ],
+});
+
 ruleTester.run('allowInGenericTypeArguments: true', rule, {
   valid: [
     'function func(): void {}',