Currently, we can specifyparserOptions.project for a path to our tsconfig, but the parser handles the loading of tsconfig, so there's no way for us to provide a custom tsconfig (not on disk) directly to@typescript-eslint/parser.

My specific use-case is that we're adding built-in TypeScript support (xojs/xo#426) to XO.XO is a "zero-config" ESLint wrapper that ships with great defaults and lots of plugins. We want to add the ability to lint ambientd.ts files. However, JS packages with ad.ts file don't usually have a tsconfig file, and I feel that TypeScript is too loose by default, so I would like to provide some sensible tsconfig defaults ford.ts files in JS projects.

It would be great if there was a way to set a default tsconfig object that is used if there's no tsconfig file in the project.