[TypeScript] Catch unsafe use of "this" in TypeScript functions

this is probably the most tricky thing to use in JavaScript and therefore TypeScript. Fortunately there is a TypeScript compiler flag noImplicit this that can help catch unsafe usages so beginners don't get caught off guard.

 

// tsconfig.json

{
  "compilerOptions": {
    "noImplicitThis": true,

...
}