API Caching & Debouncing on Mobile

1. Introduction

In the mobile-first era, optimizing API calls is essential for providing a seamless user experience. This lesson focuses on two critical techniques: caching and debouncing.

2. API Caching

Caching is the process of storing responses from API calls to reduce the number of requests made to the server. This technique is crucial for improving performance, especially in mobile applications where network latency can be a concern.

2.1 Key Concepts

• **Cache Storage:** Temporary storage of data that is frequently accessed.
• **Cache Invalidation:** The process of removing outdated data from the cache.
• **Cache Duration:** The length of time data is stored before it expires.

2.2 Implementing API Caching

Here's a basic example using a fetch request with caching:

async function fetchData(url) {
    const cacheKey = `cache-${url}`;
    const cachedResponse = localStorage.getItem(cacheKey);

    if (cachedResponse) {
        return JSON.parse(cachedResponse);
    }

    const response = await fetch(url);
    const data = await response.json();
    localStorage.setItem(cacheKey, JSON.stringify(data));

    return data;
}
            

3. Debouncing

Debouncing is a technique used to limit the number of times a function is executed, particularly in response to user actions like scrolling or typing. This is essential for improving performance and reducing unnecessary API calls.

3.1 Key Concepts

• **Debounce Delay:** The amount of time to wait before executing the function after the last event.
• **User Experience:** Reduces lag and enhances interactivity by preventing excessive calls.

3.2 Implementing Debouncing

Here's how to implement a simple debounce function:

function debounce(func, delay) {
    let timeoutId;
    return function(...args) {
        if (timeoutId) {
            clearTimeout(timeoutId);
        }
        timeoutId = setTimeout(() => {
            func.apply(this, args);
        }, delay);
    };
}

// Usage
const handleSearch = debounce(async (query) => {
    const results = await fetchData(`https://api.example.com/search?q=${query}`);
    console.log(results);
}, 300);
            

4. Best Practices

1. Use cache wisely and invalidate outdated data regularly.
2. Implement debouncing for user-triggered events to enhance performance.
3. Monitor API usage to understand patterns and optimize caching strategies.
4. Consider using libraries or frameworks that support built-in caching and debouncing mechanisms.

5. FAQ