7. What's the difference between `never` and `void`?

The keyword void literally means emptiness. A function that returns the void type does not return any value. Assigning its execution to a variable is equivalent to setting that variable to the value undefined.

The never type signifies that a value will never occur. A function returning the never type never completes execution - for instance, it might handle an infinite loop or throw an exception.

const voidFunc = (): void => {
 const a = 1 + 1;
}

console.info(voidFunc()) // undefined

const neverFunc = (): never => { // A function returning 'never' cannot have a reachable end point.
 const a = 1 + 1;
}

console.info(neverFunc()) // undefined

const neverFunc2 = (): never => {
 const a = 1 + 1;
 return a; // Type 'number' is not assignable to type 'never'.
}