更改 state 时不调用 Function

Question

I have a function in react showPeople. This is the code:

const showPeople = () => {
    const people = workers.map((worker, i) => {
        return (
            <div>
                <Worker
                    id={worker.id}
                    index={i}
                    role={worker.role}
                />
            </div>
        )
    })
    return people;
}

Later in the component I want to call this function in order to show me some information for the workers. I call it like this:

<div>
  {showPeople()}
</div> 

And this is ok, but it is called only once. When I change the state it's not called. So I have my updates only after I refresh the page. If i remove the parenthesis in the call, I get nothing on my screen. Does anyone knows what's the problem? Sorry if this question is a duplicate, I am not sure I understood any of the previous answers connected tot his topic. Thanks

Answer 1

As this is written, it should update when state updates ( see example here ). Unless you have the array workers saved for example like const {workers} = this.state or const [workers, setWorkers] = useState([{'id': '1', role: 'thisRoleNAme'}]) then you may not actually be accessing a piece of state.

Answer 2

Edit your function to accept workers as parameter:

const showPeople = (workers) => {
 const people = workers.map((worker, i) => {
    return (
        <div>
            <Worker
                id={worker.id}
                index={i}
                role={worker.role}
            />
        </div>
    )
})
return people;
}

And pass workers from state.

<div>
 {showPeople(this.state.workers)}
</div> 

It should re-render whenever your this.state.workers change and it will render with new workers.