Things to install:

//babel

npm install --save-dev @babel/core @babel/preset-env @babel/node

--> then create a file called .babelrc in the root of your project

--> INSIDE the .babelrc file, add this:

{ "presets": ["@babel/preset-env"] }

THEN...

npm i jest --save installs and saves jest to dependencies

npm i supertest --save installs and saves supertest to dependencies

npm i @babel/polyfill --save-dev installs and saves babel polyfill to dev dependencies

npm i babel-core --save-dev installs and saves babel-core to dev dependencies (DIFFERENT from the @babel/core that gets installed when you install babel)

npm i nodemon --save-dev installs nodemon to dev dependencies. doesn't seem to have anything to do with testing but who knows

npm i regenerator-runtime --save-dev