in Chapter 1, TypeScript Linting, introduced us to TSLint. Add it to your project as follows:

1. Install TSLint by entering the following command in the terminal:

 npm install tslint --save-dev

2. Add a basic tslint.json file at the root of our project, and enter the following: 

{
  "extends": ["tslint:recommended", "tslint-react", "tslint-config-prettier"],
  "linterOptions": {
    "exclude": ["node_modules/**/*.ts"]
  }
}