React useEffect

import React, { useEffect } from 'react';

export const App: React.FC = () => {
  
  useEffect(() => {
        
  }, [/*Here can enter some value to call again the content inside useEffect*/])
  
  return (
    <div>Use Effect!</div>
  );
}

How to use useeffect

import React, { useState, useEffect } from 'react';
function Example() {
  const [count, setCount] = useState(0);

  // Similar to componentDidMount and componentDidUpdate:  
  useEffect(() => {    
  	// Update the document title using the browser API    
  	document.title = `You clicked ${count} times`;  
  });
  
  return (
    <div>
      <p>You clicked {count} times</p>
      <button onClick={() => setCount(count + 1)}>
        Click me
      </button>
    </div>
  );
}

Source: reactjs.org

What is useeffect

useEffect is a hook for encapsulating code that has 'side effects,' and is like a combination of componentDidMount , componentDidUpdate , and componentWillUnmount . Previously, functional components didn't have access to the component life cycle, but with useEffect you can tap into it.23.1.2019

Useeffect react

useEffect(() => {
  window.addEventListener('mousemove', () => {});

  // returned function will be called on component unmount 
  return () => {
    window.removeEventListener('mousemove', () => {})
  }
}, [])

Source: stackoverflow.com

Useeffect react example

import React, { useEffect, useState } from "react";
import ReactDOM from "react-dom";

function Reddit() {
  // Initialize state to hold the posts
  const [posts, setPosts] = useState([]);

  // effect functions can't be async, so declare the
  // async function inside the effect, then call it
  useEffect(() => {
    async function fetchData() {
      // Call fetch as usual
      const res = await fetch(
        "https://www.reddit.com/r/reactjs.json"
      );

      // Pull out the data as usual
      const json = await res.json();

      // Save the posts into state
      // (look at the Network tab to see why the path is like this)
      setPosts(json.data.children.map(c => c.data));
    }

    fetchData();
  }); // <-- we didn't pass a value. what do you think will happen?

  // Render as usual
  return (
    <ul>
      {posts.map(post => (
        <li key={post.id}>{post.title}</li>
      ))}
    </ul>
  );
}

ReactDOM.render(
  <Reddit />,
  document.querySelector("#root")
);

Source: daveceddia.com

Useeffect

import React, { useState, useEffect } from 'react';
function Example() {
  const [count, setCount] = useState(0);

  useEffect(() => {    document.title = `You clicked ${count} times`;  });
  return (
    <div>
      <p>You clicked {count} times</p>
      <button onClick={() => setCount(count + 1)}>
        Click me
      </button>
    </div>
  );
}

Source: reactjs.org

Similar codes

1 vote191 views1 answer
Whats ruby used for
TypeScript
1 vote171 views1 answer
Download and run exploits from exploit-db
TypeScript
0 vote154 views1 answer
Embed python in html
TypeScript
-1 vote193 views1 answer
ResultSet object has no attribute 'get_text'. You're probably treating a list of elements like a single element. Did you call find_all() when you meant to call find()?
TypeScript
0 vote169 views1 answer
Typescript globalThis
TypeScript
7 votes203 views5 answers
Cannot be loaded because running scripts is disabled on this system vscode
TypeScript
1 vote265 views1 answer
'Missing locale data for the locale "pt-BR".' for pipe 'DatePipe'
TypeScript
0 vote201 views1 answer
Write a C proogram to find the roots of quadratic equation
TypeScript
0 vote176 views1 answer
Module.exports mongodb connection
TypeScript
0 vote212 views1 answer
How to run typescript in vscode
TypeScript