React state don't update

Question

I'm updating the state of an object, say like obj = { a:1, b: ['hello','bye'] } to setObj({ a:1, b:['hi','good'] }) . The react re-renders this ParentComponent.

//ParentComponent

return (
  <>
    {
      obj.b.map((data,i)=>{
        <ChildComponent greetings={data}/>
      })
    }
  </>
)

But it doesn't re-render the ChildComponent, I'm new to react and still exploring new things. Please help me out with this one.

Answer 1

If you write like this, the ChildComponent won't be render. Instead, you should add a return

    {
      obj.b.map((data,i)=>{
        return <ChildComponent greetings={data}/>
      })
    }

or

{
   obj.b.map((data,i)=>(<ChildComponent greetings={data}/>))
}