Run npm install.
Try add some errors, weird spacing, etc. and then run validate, or try commit with errors. The CLI output should stop and show you what's wrong. If your code passes, it will auto-format & auto-lint your /src files, and build.
Linting is done with eslint. The package is extended in .eslintrc to include good presets, cover typescript errors and avoid conflicts with Prettier.
Formatting is done with prettier, with config set in .prettierrc. If you have a the editor extension, you can enable format on save and it should use this config over the editor's.
typescript is used only type checking. Compiling is done by Babel, hence "noEmit": true, in the tsconfig.json.
With the presets set for the above, there is a validate script that will run and check all the above. You can run this at any time during development to find errors.
lint-staged is used to run linting and formatting when committing.
husky is used to runcheck types, run linting and formatting, and build pre-commit, so nothing broken/unformatted is ever committed.