Skip to main content

Difference between useState and props

I am new to React and I am trying to understand the difference between the following two approaches in a simple example where the button color is changed when there is a mouse hover event.

First approach using props:

  function over(props) {
    props.target.style.backgroundColor = 'black';
  };

  function out(props){
    props.target.style.backgroundColor = 'white';
  };

  return (
    <div className="container">
      <h1>{headingText}</h1>
      <input type="text" placeholder="What's your name?" />
      <button onMouseOver={over} onMouseOut={out}>Submit</button>
    </div>
  );

Second approach using useState:

  const [isMouseOver, setMouseOver] = useState(false);
 

  function handleMouseOver() {
    setMouseOver(true);
  };

  function handleMouseOut() {
    setMouseOver(false);
  };
  
  return (
    <div className="container">
      <h1>{headingText}</h1>
      <input type="text" placeholder="What's your name?" />
      <button
        onMouseOver={handleMouseOver}
        onMouseOut={handleMouseOut}
        style=
      >
        Submit
      </button>
    </div>
  );

I can see the same behavior is accomplished, but I would like to understand if technically there is any difference between these two, and if they are both valid or perhaps the first one should not be used?

Thanks in advance.

Via Active questions tagged javascript - Stack Overflow https://ift.tt/C8ilWzA

Comments

Popular posts from this blog

Why is my reports service not connecting?

I am trying to pull some data from a Postgres database using Node.js and node-postures but I can't figure out why my service isn't connecting. my routes/index.js file: const express = require('express'); const router = express.Router(); const ordersCountController = require('../controllers/ordersCountController'); const ordersController = require('../controllers/ordersController'); const weeklyReportsController = require('../controllers/weeklyReportsController'); router.get('/orders_count', ordersCountController); router.get('/orders', ordersController); router.get('/weekly_reports', weeklyReportsController); module.exports = router; My controllers/weeklyReportsController.js file: const weeklyReportsService = require('../services/weeklyReportsService'); const weeklyReportsController = async (req, res) => { try { const data = await weeklyReportsService; res.json({data}) console...

How to show number of registered users in Laravel based on usertype?

i'm trying to display data from the database in the admin dashboard i used this: <?php use Illuminate\Support\Facades\DB; $users = DB::table('users')->count(); echo $users; ?> and i have successfully get the correct data from the database but what if i want to display a specific data for example in this user table there is "usertype" that specify if the user is normal user or admin i want to user the same code above but to display a specific usertype i tried this: <?php use Illuminate\Support\Facades\DB; $users = DB::table('users')->count()->WHERE usertype =admin; echo $users; ?> but it didn't work, what am i doing wrong? source https://stackoverflow.com/questions/68199726/how-to-show-number-of-registered-users-in-laravel-based-on-usertype

The number of nodes and edges I calculated manually and by a method provided by networkx library dont match

I am trying to analyse a graph using networkx library in Python. I have implemented a function that returns the nodes and edges of that graph. After that I counted the number of nodes and edges by implementing the len() function for nodes and edges, which gave me 17 for both nodes and edges. However, when I used the method graph.number_of_nodes() of networkx library it gave me 53. My code: import pandas as pd import networkx as nx import matplotlib.pyplot as plt header_list = ["a","b","w"] E =pd.read_csv("aves-barn-swallow-contact-network.edges",sep=" ",header= None,names=header_list) # print(E.head()) # prints first few rows of the csv file G = nx.from_pandas_edgelist(E,"a","b",["w"]) nx.draw(G) plt.show() class GraphAnalyse: #finding nodes and edges def nodeEdge(self,Graph): nodes = Graph.nodes() edges = Graph.edges() ...