VS Code

launch.json:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Mocha tests",
            "type": "node",
            "request": "launch",
            "program": "${workspaceRoot}/node_modules/.bin/_mocha",
            "args": ["-u", "tdd", "--timeout", "999999", "--colors", "src/**/*.test.js", "bin/*.test.js"],
            "internalConsoleOptions": "openOnSessionStart"
        }
    ]
}

Auto format with prettier on save:

npm install --save-dev babel-eslint eslint eslint-config-prettier eslint-plugin-prettier prettier

settings.json:

{
    "eslint.autoFixOnSave": true
}