javascript - How to do a nested if else statement in ReactJS JSX?

Question

I wanted to know if its possible to do nested if else if in ReactJS JSX?

I have tried various different ways and I am unable to get it to work.

I am looking for

if (x) {
  loading screen
} else {
  if (y) {
    possible title if we need it
  }
  main 
}

I have tried this but I can not get it to render. I have tried various ways. It always breaks once I add the nested if.

{
  this.state.loadingPage ? (
    <div>loading page</div>
  ) : (
    <div>
      this.otherCondition && <div>title</div>
      <div>body</div>
    </div>
  );
}

Update

I ended up choosing the solution to move this to renderContent and call the function. Both of the answers did work though. I think I may use the inline solution if it is for a simple render and renderContent for more complicated cases.

Thank you

Answer 1

You need to wrap your title and body in a container. That could be a div. If you use a list instead, you'll have one less element in the dom.

{ this.state.loadingPage
  ? <span className="sr-only">Loading... Registered Devices</span>
  : [
      (this.state.someBoolean
        ? <div key='0'>some title</div>
        : null
      ),
      <div key='1'>body</div>
    ]
}

I would advise against nesting ternary statements because it's hard to read. Sometimes it's more elegant to "return early" than to use a ternary. Also, you can use isBool && component if you only want the true part of the ternary.

renderContent() {
  if (this.state.loadingPage) {
    return <span className="sr-only">Loading... Registered Devices</span>;
  }

  return [
    (this.state.someBoolean && <div key='0'>some title</div>),
    <div key='1'>body</div>
  ];
}

render() {
  return <div className="outer-wrapper">{ this.renderContent() }</div>;
}

Caveat to the syntax someBoolean && "stuff": if by mistake, someBoolean is set to 0 or NaN, that Number will be rendered to the DOM. So if the "boolean" might be a falsy Number, it's safer to use (someBoolean ? "stuff" : null).