fix: for "typescript" mode, require object shorthand or index signatures

.README/rules/check-types.md

@@ -103,7 +103,8 @@ object.
 
 However, `Object.create(null)` objects are not `instanceof Object`, however, so
 in the case of such a plain object we lower-case to indicate possible support
-for these objects. Also, nowadays, TypeScript also discourages use of `Object`
+for these objects. Also, nowadays, TypeScript also [discourages](https://www.typescriptlang.org/docs/handbook/declaration-files/do-s-and-don-ts.html#:~:text=%E2%9D%8C%20Don't%20ever%20use,used%20appropriately%20in%20JavaScript%20code.)
+use of `Object`
 as a lone type. However, one additional complexity is that TypeScript allows and
 actually [currently requires](https://github.com/microsoft/TypeScript/issues/20555)
 `Object` (with the initial upper-case) if used in the syntax
@@ -112,8 +113,14 @@ adhere to that which [JSDoc documents](https://jsdoc.app/tags-type.html).
 
 So, for optimal compatibility with TypeScript (especially since TypeScript
 tools can be used on plain JavaScript with JSDoc), we are now requiring this
-TypeScript approach by default (if you set `object` type `preferredTypes` in
-TypeScript mode, the defaults will not apply).
+TypeScript approach by default in non-"typescript" mode (if you set
+`object` type `preferredTypes` in TypeScript mode, the defaults will
+not apply).
+
+However, for "typescript" mode, a still better choice exists—using index signatures such as `{[key: string]: string}` or using a more precise
+shorthand object syntax (e.g., `{a: string, b: number}`). This is superior
+for TypeScript because the likes of `Object<string, number>` is not useable
+in native TypeScript syntax, even if it is allowed within JSDoc.
 
 Basically, for primitives, we want to define the type as a primitive, because
 that's what we use in 99.9% of cases. For everything else, we use the type

README.md

@@ -5442,7 +5442,8 @@ object.
 
 However, `Object.create(null)` objects are not `instanceof Object`, however, so
 in the case of such a plain object we lower-case to indicate possible support
-for these objects. Also, nowadays, TypeScript also discourages use of `Object`
+for these objects. Also, nowadays, TypeScript also [discourages](https://www.typescriptlang.org/docs/handbook/declaration-files/do-s-and-don-ts.html#:~:text=%E2%9D%8C%20Don't%20ever%20use,used%20appropriately%20in%20JavaScript%20code.)
+use of `Object`
 as a lone type. However, one additional complexity is that TypeScript allows and
 actually [currently requires](https://github.com/microsoft/TypeScript/issues/20555)
 `Object` (with the initial upper-case) if used in the syntax
@@ -5451,8 +5452,14 @@ adhere to that which [JSDoc documents](https://jsdoc.app/tags-type.html).
 
 So, for optimal compatibility with TypeScript (especially since TypeScript
 tools can be used on plain JavaScript with JSDoc), we are now requiring this
-TypeScript approach by default (if you set `object` type `preferredTypes` in
-TypeScript mode, the defaults will not apply).
+TypeScript approach by default in non-"typescript" mode (if you set
+`object` type `preferredTypes` in TypeScript mode, the defaults will
+not apply).
+
+However, for "typescript" mode, a still better choice exists—using index signatures such as `{[key: string]: string}` or using a more precise
+shorthand object syntax (e.g., `{a: string, b: number}`). This is superior
+for TypeScript because the likes of `Object<string, number>` is not useable
+in native TypeScript syntax, even if it is allowed within JSDoc.
 
 Basically, for primitives, we want to define the type as a primitive, because
 that's what we use in 99.9% of cases. For everything else, we use the type
@@ -6132,7 +6139,7 @@ function quux (foo) {
 
 }
 // Settings: {"jsdoc":{"mode":"typescript"}}
-// Message: Invalid JSDoc @param "foo" type "object"; prefer: "Object<>".
+// Message: Use object shorthand or index signatures instead of `object`, e.g., `{[key: string]: string}`
 
 /**
  *
@@ -6414,7 +6421,7 @@ function b () {}
 function a () {}
 
 /**
- * @typedef {Object<string>} foo
+ * @typedef {{[key: string]: number}} foo
  */
 function b () {}
 // Settings: {"jsdoc":{"mode":"typescript"}}
@@ -6443,7 +6450,7 @@ function quux (foo) {
 }
 
 /**
- * @param {Object<string>} foo
+ * @param {{[key: string]: number}} foo
  */
 function quux (foo) {
 

src/rules/checkTypes.js

@@ -73,6 +73,11 @@ const adjustNames = (type, preferred, isGenericMatch, typeNodeName, node, parent
   }
 };
 
+const getMessage = (upperCase) => {
+  return 'Use object shorthand or index signatures instead of ' +
+  '`' + (upperCase ? 'O' : 'o') + 'bject`, e.g., `{[key: string]: string}`';
+};
+
 export default iterateJsdoc(({
   jsdocNode,
   sourceCode,
@@ -97,13 +102,35 @@ export default iterateJsdoc(({
     'Object.<>' in preferredTypesOriginal ||
     'object<>' in preferredTypesOriginal);
 
-  const preferredTypes = {
-    ...injectObjectPreferredTypes ? {
+  const info = {
+    message: getMessage(),
+    replacement: false,
+  };
+
+  const infoUC = {
+    message: getMessage(true),
+    replacement: false,
+  };
+
+  const typeToInject = mode === 'typescript' ?
+    {
+      Object: 'object',
+      'object.<>': info,
+      'Object.<>': infoUC,
+      'object<>': info,
+      'Object<>': infoUC,
+    } :
+    {
       Object: 'object',
       'object.<>': 'Object<>',
       'Object.<>': 'Object<>',
       'object<>': 'Object<>',
-    } : {},
+    };
+
+  const preferredTypes = {
+    ...injectObjectPreferredTypes ?
+      typeToInject :
+      {},
     ...preferredTypesOriginal,
   };
 
@@ -364,7 +391,7 @@ export default iterateJsdoc(({
       for (const [
         badType,
         preferredType = '',
-        message,
+        msg,
       ] of invalidTypes) {
         const tagValue = jsdocTag.name ? ` "${jsdocTag.name}"` : '';
         if (exemptTagContexts.some(({
@@ -378,13 +405,13 @@ export default iterateJsdoc(({
         }
 
         report(
-          message ||
+          msg ||
             `Invalid JSDoc @${tagName}${tagValue} type "${badType}"` +
             (preferredType ? '; ' : '.') +
             (preferredType ? `prefer: ${JSON.stringify(preferredType)}.` : ''),
           preferredType ? fix : null,
           jsdocTag,
-          message ? {
+          msg ? {
             tagName,
             tagValue,
           } : null,

test/rules/assertions/checkTypes.js

@@ -2339,17 +2339,9 @@ export default {
       errors: [
         {
           line: 3,
-          message: 'Invalid JSDoc @param "foo" type "object"; prefer: "Object<>".',
+          message: 'Use object shorthand or index signatures instead of `object`, e.g., `{[key: string]: string}`',
         },
       ],
-      output: `
-        /**
-         * @param {Object<string>} foo
-         */
-        function quux (foo) {
-
-        }
-      `,
       settings: {
         jsdoc: {
           mode: 'typescript',
@@ -2944,7 +2936,7 @@ export default {
         function a () {}
 
         /**
-         * @typedef {Object<string>} foo
+         * @typedef {{[key: string]: number}} foo
          */
         function b () {}
       `,
@@ -3020,7 +3012,7 @@ export default {
     {
       code: `
       /**
-       * @param {Object<string>} foo
+       * @param {{[key: string]: number}} foo
        */
       function quux (foo) {