mixly3/boards/default_src/arduino_avr/jsconfig.json

{
    "compilerOptions": {
        "experimentalDecorators": true,
        "baseUrl": "./",
        "paths": {
            "@mixly/arduino": [
                "../arduino"
            ]
        }
    },
    "exclude": [
        "node_modules",
        "dist"
    ]
}