Drop support for TypeScript < 4.8

Author: fasttime

README.md

@@ -6,7 +6,7 @@
 
 Make sure that you are using a version of Node.js supported by your version of ESLint.
 See prerequisites for [ESLint 8](https://eslint.org/docs/v8.x/use/getting-started#prerequisites) and [ESLint 9](https://eslint.org/docs/v9.x/use/getting-started#prerequisites).
-For TypeScript support, you need TypeScript 4.6 or later.
+For TypeScript support, you need TypeScript 4.8 or later.
 
 To install gulp-eslint-new, [use](https://docs.npmjs.com/cli/install) [npm](https://docs.npmjs.com/about-npm):
 

eslint.config.js

@@ -7,9 +7,7 @@ const globals           = require('globals');
 module.exports =
 createConfig
 (
-    {
-        ignores: ['**/.*', 'coverage', 'example/demo'],
-    },
+    { ignores: ['**/.*', 'coverage', 'example/demo'] },
     {
         files:              ['**/*.js'],
         jsVersion:          2020,
@@ -21,8 +19,7 @@ createConfig
     },
     {
         files:              ['**/*.ts'],
-        tsVersion:          '4.6.0',
-        languageOptions:    { parserOptions: { project: 'tsconfig.json' } },
+        tsVersion:          '4.8.0',
         plugins:            { 'tsdoc': eslintPluginTsdoc },
         rules:              { 'tsdoc/syntax': 'error' },
     },

gulpfile.js

@@ -94,6 +94,6 @@ function tsTest(tsVersion, tsPkgName)
     return task;
 }
 
-task('ts-test', parallel(tsTest('4.6', 'typescript_4.6'), tsTest('5', 'typescript_5')));
+task('ts-test', parallel(tsTest('4.8', 'typescript_4.8'), tsTest('5', 'typescript_5')));
 
 task('default', series('clean', parallel('lint', 'ts-test'), 'test'));

lib/eslint.d.ts

@@ -4,17 +4,18 @@ type ESLintrcOptions = ESLint.LegacyOptions;
 
 type FlatESLintOptions = ESLint.Options;
 
+// In @types/eslint `ESLint.LintResultData` lacks the `maxWarningsExceeded` property.
 type FormatterContext = ESLint.LintResultData & ResultsMeta;
 
 type FormatterFunction =
-(results: ESLint.LintResult[], context?: FormatterContext) => string | Promise<string>;
+(results: ESLint.LintResult[], context: FormatterContext) => string | Promise<string>;
 
 type LintMessage = Linter.LintMessage;
 
 type LintResult = ESLint.LintResult;
 
 interface LoadedFormatter
-{ format(results: ESLint.LintResult[], resultsMeta: ResultsMeta): string | Promise<string>; }
+{ format(results: ESLint.LintResult[], resultsMeta?: ResultsMeta): string | Promise<string>; }
 
 interface ResultsMeta
 {