Using Prettier to automatically fix syntax for you

npm i -D Prettier

# Pretty a file
npm prettier src/Filename.js --write

# Prettier config file
touch ~/.prettierrc

{}

{} just means take everything default. VS Code will automatically start using prettier to format your files if it sees a .prettierrc file. Make sure you have the following settings enabled in VS Code settings

# VS Code config
Editor: Format On Save
Prettier: Require Config

"scrpts": {
    "format": "prettier --write 'src/**/*.{js,jsx,html,css,json}'"
}

https://frontendmasters.com/courses/complete-react-v4/adding-prettier-cli-script/

ESLint

Prettier handles formatting (spacing etc.), ESLint handles stylistic choices (variables not being used)

With ESLint you can use the Standard, Airbnb or ESLint recommended rules.

npm i -D eslint eslint-config-prettier eslint-plugin-prettier

You can see what ESLint did with the --debug flag

"scrpts": {
    "lint": "eslint '**/*.{js,jsx}'"
}

eslint 'src/**/*.{js,jsx}' --debug

# the -- let's it know that we want to pass in ore params with the npm command
npm run lint -- --debug

ESLint came after JSHint which came after JSLint

// allow these globals and don't warn for them
"globals": {
    "React": true
}