Old projects (ESLint 8)

An Angular 18 project on ESLint 8 cannot use the flat configs of lint/eslint/. lint/legacy/angular-18.eslintrc.json gives it the same rules and the same levels, in the old format, in one file to paste as .eslintrc.json.

• Generated from the Angular application preset, and checked with ESLint 8.57.1, typescript-eslint 8 and angular-eslint 18.4: every rule exists in those versions and every option is valid. The settings that came in later versions are adapted, with a comment (OnPush is required explicitly: it is not the default before Angular 22).
• The levels: errors, then warnings, then the infos, off (ESLint 8 has no info level: set one to "warn" to see it), then the rules off on purpose. Each rule keeps its comment (.eslintrc.json accepts comments).
• Specs relax the warnings and the hacks (any, !), like the flat configs.
• Inline templates are linted with the *.html rules (@angular-eslint/template/extract-inline-html).
• Not included: SonarJS, import-x, Prettier and the rules written here (file names, one export per file, folder imports, disable comments only on warnings): their plugins are not installed in those projects.

It needs eslint 8.57, @typescript-eslint/parser and @typescript-eslint/eslint-plugin 8, @angular-eslint/eslint-plugin, @angular-eslint/eslint-plugin-template and @angular-eslint/template-parser 18.