// Why this is not working

function runAfter1s(fn: () => number){
    setTimeout(fn, 1000)
}

const doSomething: () => void = () => {
    console.log('Hello')
    return 5;  
}

runAfter1s(doSomething)

Why this is working

function runAfter1s(fn: () => void){
setTimeout(fn, 1000)
> }

const doSomething: () => void = () => {
console.log('Hello')
return 5; 
> }

runAfter1s(doSomething)

I think second one should throw error because we are returning a number while doSomething is defined as void and in first while I have specified dooSomething as void is returning error