Conditional Rendering in LemonadeJS

LemonadeJS supports conditional rendering through a special attribute: :render (or lm-render). This allows you to dynamically show or hide sections of the DOM based on boolean conditions, making your components reactive and clean.

How It Works

You can use the :render (or lm-render) attribute on a container element. It expects a boolean value. If the value is:

true: the content inside the container is rendered and added to the DOM.
false: the content is removed, leaving only the container itself in the DOM.

This becomes powerful when used with reactive state or component properties to dynamically toggle visibility.

Attribute Reference

Attribute	Description
`:render` / `lm-render`	Conditionally controls whether the content inside a container is rendered.

Examples

Using Component Properties

This example toggles an input field based on a component’s internal property.

<html>
<script src="https://lemonadejs.com/v5/lemonade.js"></script>
<div id="root"></div>
<script>
function Component() {
  this.test = 'hidden';

  const toggle = () => {
    this.test = this.test === 'visible' ? 'hidden' : 'visible';
  }

  return render => render`<div>
    <div :render="${this.test === 'visible'}">
      <input type="text" />
    </div>
    <input type="button" value="Toggle Input" onclick="${toggle}" />
  </div>`;
}

lemonade.render(Component, document.getElementById('root'));
</script>
</html>

export default function Component() {
    this.test = 'hidden';

    const toggle = () => {
        this.test = this.test === 'visible' ? 'hidden' : 'visible';
    }

    return render => render`<div>
        <div :render="${this.test === 'visible'}">
          <input type="text" />
        </div>
        <input type="button" value="Toggle Input" onclick="${toggle}" />
      </div>`;
    }

Using Reactive `state`

Here’s a version using LemonadeJS’s state() to create a reactive in the private context of the component.

HTML Script Version

<html>
<script src="https://lemonadejs.com/v5/lemonade.js"></script>
<div id="root"></div>
<script>
function Component(children, { state }) {
  let data = state(false);

  const toggle = () => {
    data.value = !data.value;
  }

  return render => render`<div>
    <div :render="${data}">
      <input type="text" />
    </div>
    <input type="button" value="Toggle Input" onclick="${toggle}" />
  </div>`;
}

lemonade.render(Component, document.getElementById('root'));
</script>
</html>

export default function Test(children, { state }) {
  let data = state(false);

  const toggle = () => {
    data.value = !data.value;
  }

  return render => render`<div>
    <div :render="${data}">
      <input type="text" />
    </div>
    <input type="button" value="Toggle Input" onclick="${toggle}" />
  </div>`;
}

What’s Next?

Explore how LemonadeJS simplifies working with forms using reactive data bindings and dynamic field generation.

Explore Dynamic Forms

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