reactjs – Page 141 – Tarik Billa

Invariant Violation: Could not find “store” in either the context or props of “Connect(SportsDatabase)”

October 24, 2022 by Tarik

It’s pretty simple. You’re trying to test the wrapper component generated by calling connect()(MyPlainComponent). That wrapper component expects to have access to a Redux store. Normally that store is available as context.store, because at the top of your component hierarchy you’d have a <Provider store={myStore} />. However, you’re rendering your connected component by itself, with … Read more

What does it mean when they say React is XSS protected?

October 24, 2022 by Tarik

ReactJS is quite safe by design since String variables in views are escaped automatically With JSX you pass a function as the event handler, rather than a string that can contain malicious code so a typical attack like this will not work const username = “<img onerror=”alert(\”Hacked!\”)” src=”https://stackoverflow.com/questions/33644499/invalid-image” />”; class UserProfilePage extends React.Component { render() … Read more

configuration.module has an unknown property ‘loaders’

October 23, 2022 by Tarik

You should change loaders to rules in webpack 4: change: loaders to: rules source: Loaders Example: module.exports = { module: { rules: [ { test: /\.css$/, use: ‘css-loader’ }, { test: /\.ts$/, use: ‘ts-loader’ } ] } };

‘React’ was used before it was defined

October 23, 2022 by Tarik

From the official documentation. “rules”: { // note you must disable the base rule as it can report incorrect errors “no-use-before-define”: “off”, “@typescript-eslint/no-use-before-define”: [“error”] }

How to center a component in MUI and make it responsive?

October 23, 2022 by Tarik

Since you are going to use this on a login page. Here is a code I used in a Login page using Material-UI MUI v5 <Grid container spacing={0} direction=”column” alignItems=”center” justifyContent=”center” style={{ minHeight: ‘100vh’ }} > <Grid item xs={3}> <LoginForm /> </Grid> </Grid> MUI v4 and below <Grid container spacing={0} direction=”column” alignItems=”center” justify=”center” style={{ minHeight: … Read more

How to declare a global variable in React?

October 22, 2022 by Tarik

Beyond React You might not be aware that an import is global already. If you export an object (singleton) it is then globally accessible as an import statement and it can also be modified globally. If you want to initialize something globally but ensure its only modified once, you can use this singleton approach that … Read more

Infinite loop in useEffect

October 22, 2022 by Tarik

Passing an empty array as the second argument to useEffect makes it only run on mount and unmount, thus stopping any infinite loops. useEffect(() => { setIngredients({}); }, []); This was clarified to me in the blog post on React hooks at https://www.robinwieruch.de/react-hooks/

How to use Google fonts in React.js?

October 22, 2022 by Tarik

In some sort of main or first loading CSS file, just do: @import url(‘https://fonts.googleapis.com/css?family=Source+Sans+Pro:regular,bold,italic&subset=latin,latin-ext’); You don’t need to wrap in any sort of @font-face, etc. the response you get back from Google’s API is ready to go and lets you use font families like normal. Then in your main React app JavaScript, at the top … Read more

Receiving “Attempted import error:” in react app

October 22, 2022 by Tarik

import { combineReducers } from ‘../../store/reducers’; should be import combineReducers from ‘../../store/reducers’; since it’s a default export, and not a named export. There’s a good breakdown of the differences between the two here.

How to disable a button when an input is empty?

October 22, 2022 by Tarik

You’ll need to keep the current value of the input in state (or pass changes in its value up to a parent via a callback function, or sideways, or <your app’s state management solution here> such that it eventually gets passed back into your component as a prop) so you can derive the disabled prop … Read more