Understanding the Error Handling API in Svelte Components

Svelte provides an error handling API that allows you to handle and manage errors within your components. This API enables you to gracefully handle errors and provide fallback behavior or error messages to the users of your application.

To implement error handling in a Svelte component, you can use the <svelte:error> component and the error block.

Here's an example of how to use the error handling API in a Svelte component:

<script>
  let data;
 
  async function fetchData() {
    try {
      const response = await fetch('https://api.example.com/data');
      data = await response.json();
    } catch (error) {
      console.error('Error fetching data:', error);
      throw new Error('Failed to fetch data');
    }
  }
</script>
 
<svelte:head>
  <title>Error Handling Demo</title>
</svelte:head>
 
<button on:click={fetchData}>Fetch Data</button>
 
{#if data}
  <ul>
    {#each data as item}
      <li>{item}</li>
    {/each}
  </ul>
{:else}
  <svelte:error>
    <p>Error fetching data. Please try again later.</p>
  </svelte:error>
{/if}

In the example above, the fetchData function attempts to fetch data from an API endpoint. If an error occurs during the fetch operation, it is caught in the catch block. In this case, we log the error to the console and throw a new error with a custom message.

Within the component's template, we conditionally render the fetched data. If data is present, we iterate over it and display it in an <ul> element. If data is not available (i.e., an error occurred), we display a fallback error message using the <svelte:error> component. The content inside the <svelte:error> component is rendered when an error occurs within the component.

By using the error handling API in Svelte, you can provide a more robust and user-friendly experience when errors occur. You have the flexibility to display custom error messages, perform error logging, or trigger other appropriate actions based on your application's needs.