void

void represents the return value of functions which don’t return a value. It’s the inferred type any time a function doesn’t have any return statements, or doesn’t return any explicit value from those return statements:

// The inferred return type is void
function noop() {
  return;
}

In JavaScript, a function that doesn’t return any value will implicitly return the value undefined. However, void and undefined are not the same thing in TypeScript. There are further details at the end of this chapter.

Learn more from the following links:

• void - TypeScript Docs