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

Solution 1:

You need to wrap your title and body in a container. That could be a div. If you use a fragment 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>some title</div>
        : null
      }
      <div>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>some title</div>}
      <div>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).

Solution 2:

Instead of nesting ternary operators as it is often suggested or creating a separate function that will not be reused anywhere else, you can simply call an inline expression:

<div className="some-container">
{
   (() => {
       if (conditionOne)
          return <span>One</span>
       if (conditionTwo)
          return <span>Two</span>
       else (conditionOne)
          return <span>Three</span>
   })()
}
</div>

Solution 3:

You can check multiple conditions to render components accordingly like below:

  this.state.route === 'projects'
  ? 
  <div> <Navigation onRouteChange={this.onRouteChange}/> Projects</div>
  :
  this.state.route === 'about'
  ?
  <div> <Navigation onRouteChange={this.onRouteChange}/> About</div>
  :
  this.state.route === 'contact'
  ?
  <div> <Navigation onRouteChange={this.onRouteChange}/> Contact</div>
  :
  <p> default </p>

Solution 4:

You can nest as many statements as possible. please follow this code assuming that this.state.firstTestValue, this.state.someTestValue and this.state.thirdValueTest are your test values from the state.

{this.state.firstTestValue
    ? <div >First Title</div>
    : [
        this.state.someTestValue
            ? <div>Second Title</div>
            : [
                this.state.thirdValueTest 
                ? <div>Some Third Title</div> 
                : <div>Last Title</div>
            ]
    ]
}

Solution 5:

Your code in the alternative is not valid JavaScript/JSX expression:

(
  this.state.someBoolean ?
  (<div>some title</div>):(<div>some other title</div>)
  <div>body</div>
)

Lets simplify this to

(
  true ? 42 : 21
  3
)

This throws the error

Uncaught SyntaxError: Unexpected number(…)

You cannot just have two expression next to each other.

Instead you have to return a single value from the false branch of the conditional operator. You can do this by simply putting it in another JSX element:

(
  <div>
    {this.state.someBoolean ? (<div>some title</div>) : (<div>some other title</div>)}
    <div>body</div>
  </div>
)

If you want to only show "body" when "some other title" is shown, you need to move <div>body</div> into the false branch of the conditional operator:

(
  this.state.someBoolean ?
    (<div>some title</div>) :
    (<div>
       <div>some other title</div>
       <div>body</div>
    </div>)
)

Or maybe you want

(
  <div>
    {this.state.someBoolean ? (<div>some title</div>) : null}
    <div>body</body>
  </div>
)