How to CSS display:none within conditional with React JSX?

119,541

Solution 1

This is due to incorrect usage of the ternary operator. See documentation here: https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Operators/Conditional_Operator

You should not wrap it with {} as you have done.

Try the following:

style={{display: this.state.showStore ? 'block' : 'none' }}

Solution 2

You can also change a classname and style in CSS.

// outside render
const NORMAL = "row account stores"
const HIDDEN = NORMAL + " hidden"

// In render
render: function() {
  return(
    <div className={this.state.showStore ? NORMAL : HIDDEN}>
      <div>a lot more divs</div>
        </div>
  );
}

Note that it is generaly better to not use double curly braces {{ in render function as you are often creating a new object on every render execution. for example:

{display: true ? 'block' : 'none' } === {display: true ? 'block' : 'none' } // false

// outside render
const BLOCK = { display: 'block' }
const NONE= { display: 'none' }

// in render
{this.state.showStore ? BLOCK : NONE}

Solution 3

You can also conditionally create the element via

   { 
     this.state.showStore 
     ? <div className="row account stores">
        <div>a lot more divs</div>
       </div> 
     : null 
   }
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StandardNerd
Author by

StandardNerd

Updated on July 09, 2022

Comments

  • StandardNerd
    StandardNerd 6 months

    I'm trying to render a div on the same page when the user clicks on a link.

    My HTML page:

    <div class="stores">
      <h1>Stores</h1>
      <ul class="stores">
        <li><a href="#" onClick={this.onClick} >Store A</a></li>
        <li>Store B</li>
        <li>Store C</li>
      </ul>
    </div>
    

    My components/store.js.jsx:

    var Store = React.createClass({
      getInitialState: function() {
        return { showStore: false };
      },
      onClick: function() {
          this.setState({ showStore: true });
      },
      render: function() {
      return(
        <div className="row account stores" style={{display: { this.state.showStore ? 'block' : 'none'} }}>
          <div>a lot more divs</div>
            </div>
        );
      }
    });
    

    But I get a:

    SyntaxError: unknown: Unexpected token

    For this line:

    style={{display: { this.state.showStore ? 'block' : 'none'} }}
    

    How can I nest conditionally inside a style?

  • wiktor
    wiktor about 6 years
    I can't find in the React documentation, but if you set a style attribute to null React doesn't add the attribute to the DOM node at all. So the following only set display: none or nothing based on the condition. style={{ display: isHidden ? 'none' : null }} This is useful if you specify display value in css - for example some form of flexbox - and you don't want to hardcode this value in javascript.
  • cquezel
    cquezel over 4 years
    @wiktor you might have read this in the classname library
  • wiktor
    wiktor over 4 years
    @cquezel Possible. Unfortunately, I did not remember what was the original source of the truth. :( I just use it.