Vanilla JS typechecking

tsconfig.json

{
    "compilerOptions": {
        "lib": ["es2017", "dom", "es2019.object", "dom.iterable"],
        "allowJs": true,     
        "checkJs": true,   
        "noEmit": true,
        "strict": false,
        "noImplicitReturns": false,
        "noFallthroughCasesInSwitch": true,     
        "noImplicitThis": false,
        "esModuleInterop": true,
        "allowSyntheticDefaultImports": true,
        "downlevelIteration": true
    },
    "include": ["./**/*"],
    "exclude": ["./node_modules/**/*"],
    "exclude": ["./static/**/*"]
}