Conditional Rendering in Svelte

In this tutorial, we are going to learn about how to render elements conditionally in svelte.js.

What is conditional rendering?

Conditional rendering means to show or hide elements from the dom based on the particular condition.

Svelte has a special syntax to render elements conditionally.

{#if isActive}
    <h1>Im active</h1>
{/if}

Note: # indicates the block opening and / indicates block closing.

Let’s see an example.

<script>
   let isActive = true;</script>

  <div>
      {#if isActive}         <h1>Im active</h1>      {/if}  </div>

In the above code, we only render the h1 element into the dom if isActive property is true.

Else block

We can also combine if block with else block.

<script>
   let isActive = true;</script>

  <div>
      {#if isActive}
         <h1>You can see me</h1>
         {:else}         <h2>You can't see me</h2>      {/if}
  </div>

Else if block

We can also further chain it with else if block.

<script>
  let isActive = true;</script>

<div>
  {#if isActive === true}
    <h1>You can see me</h1>
  {:else if isActive === 4}    <h1>You can see me only if isActive is 4</h1>  {:else}
    <h2>You can't see me</h2>
  {/if}
</div>

In the above code, we only render else if block h1 element if isActive === 4.