REACT API MASTER CLASS /// USEEFFECT /// FETCH DATA /// HANDLE PROMISES /// JSON /// REACT API MASTER CLASS ///

React APIs

Master data fetching. Connect your React components to external REST APIs using useEffect and fetch.

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Tutor:Welcome! To display dynamic data in React, we need to interact with APIs. The modern way to handle this in functional components is using the `useEffect` hook combined with the `fetch` API.

Skill Matrix

UNLOCK NODES BY MASTERING HOOKS.

1. Setup State

Before fetching, prepare your component. Track `data`, `loading`, and `error`.

System Check

Why track a loading state?

React APIs & Data Fetching

React is purely a view library. To display real, dynamic data, it must communicate with an external server through an Application Programming Interface (API).

1. The Role of useEffect

We cannot fetch data directly in the main body of a component. Doing so triggers a fetch on every render, and updating state after fetching triggers a re-render... resulting in an infinite loop. We solve this by placing side effects inside the useEffect hook.

2. The Dependency Array

The second argument of useEffect is an array of dependencies. If you leave it out, the effect runs after every render. If you pass an empty array [], it runs exactly once when the component first mounts.

3. Handling States

A robust data-fetching component requires at least three pieces of state:

1. data (to store the payload)
2. loading (boolean, true until fetch completes)
3. error (to store message if something fails)

React APIs Glossary

fetch()

A native JavaScript API used to make asynchronous network requests. Returns a Promise.

snippet.js

useEffect()

A React Hook that lets you synchronize a component with an external system or API.

snippet.js

JSON

JavaScript Object Notation. The standard format for data exchange on the web.

snippet.js

Dependency Array

An array passed to useEffect that determines when the effect should re-run.

snippet.js

Loading State

A UI pattern used to show a spinner or skeleton while data is being fetched.

snippet.js

async / await

Syntactic sugar in JS for handling Promises, making async code look synchronous.

snippet.js
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