Скачать или смотреть Caching API Results in Svelte

Learn how to cache API results in Svelte using stores and local storage for better performance and user experience.
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This video is based on the question https://stackoverflow.com/q/64092593/ asked by the user 'nuckle' ( https://stackoverflow.com/u/9291272/ ) and on the answer https://stackoverflow.com/a/64095328/ provided by the user 'dagalti' ( https://stackoverflow.com/u/9489397/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Caching API Results in Svelte

When building web applications, one of the most common challenges developers face is managing API calls efficiently. With frequent component re-renders or page refreshes, you can end up making unnecessary API calls that can not only slow down your application but also overload your server. In this guide, we will explore how to effectively cache API results in Svelte so that your application doesn't trigger the same API call every time a component renders.

The Problem

Imagine you want to display guides fetched from an external API. However, you don't want to make an API request every single time your component renders or when the user navigates through the application. Instead, you want to pull content from a cache until a certain condition is met, prompting a fresh API request.

Here is a simplified version of the code you're probably working with:

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In the scenario above, every navigation or refresh leads to a new API call, which is inefficient. So, how can we change this?

The Solution

To avoid unnecessary API calls and improve the efficiency of your application, we can use Svelte stores and local storage to cache the data. Let’s break down the steps:

1. Set Up Svelte Stores for Caching

First, we need to create a store to hold our guides and a timeout flag to determine if we need to refetch the data.

./stores.js

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2. Fetching and Caching Data in the Component

Next, modify your component to use the store we created. This will allow the component to check if there is already cached data when it mounts.

./posts.svelte

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3. Implement Local Storage for Persistent Caching

To ensure that cached data does not disappear upon refresh, we can utilize localStorage. Below is the enhanced code that uses localStorage to cache the posts.

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Summary of Steps

Create Svelte Stores: Use writable stores to hold your API data and manage state easily.

Fetch and Cache in Component: Use the store on component mount to get cached data or fetch new data as needed.

Utilize Local Storage: Store data in local storage to persist the cache between page refreshes; define a cache timeout to refresh data at appropriate intervals.

With this structure, you can significantly improve the performance and user experience of your Svelte application by reducing redundant API calls. Caching is a powerful technique that provides a smoother and faster interface for users.

By following these techniques, you'll ensure that your components use stored data whenever possible, ultimately leading to a more responsive application.