reactjs

问题 I have a javascript array like this: const IMGS = [{ id: 0, path: "../img/a1.jpeg", }, { id: 1, path: "../img/a1-01.jpeg", }, { id: 2, path: "../img/a1-02.jpeg", }, { id: 3, path: "../img/a1-03.jpeg", } ] export default IMGS; There are more images I am just showing few of them, I need to show all the images in react from this array. The condition is the image_id should be >=18 but <30 . How can I achieve that? (I need to know the syntax). I know I can do it using filter or map function,

问题 I have a javascript array like this: const IMGS = [{ id: 0, path: "../img/a1.jpeg", }, { id: 1, path: "../img/a1-01.jpeg", }, { id: 2, path: "../img/a1-02.jpeg", }, { id: 3, path: "../img/a1-03.jpeg", } ] export default IMGS; There are more images I am just showing few of them, I need to show all the images in react from this array. The condition is the image_id should be >=18 but <30 . How can I achieve that? (I need to know the syntax). I know I can do it using filter or map function,

问题 How to change this class base Context API to reach Hook without changing other components that already consumed it? I am new to react and spend all night and I got stuck. The actual code is more than this but I'm trying to remove some of the code for simplicity purposes: import React, { createContext, Component } from 'react' const MainContext = createContext(); class MainContextProvider extends Component { state = { isLogin : false, loginData : [], spinner : false } handleUserLogin = (res) =

问题 So, i am using jest for testing my node function which is calling fetch() APi to get the data, now when I am writing the test cases for the same i am getting an error like : expect(received).resolves.toEqual() Matcher error: received value must be a promise Received has type: function Received has value: [Function mockConstructor] my function : export function dataHandler (req, res, next) { const url= "someURL" if (url ) { return fetch(url ) .then((response) => response.json()) .then(

问题 I am trying to achieve this : While trying, I created an JavaScript Object(JSON like object) to access it. Here's the code: export default [ { weekMonth: 'February', weekDayofWeek: ['Thur', 'Thur', 'Thur', 'Thur'], weekDays: [ '04', '11', '18', '25'], weekStatus: 'Available +', className: 'February' }, { weekMonth: 'March', weekDayofWeek: ['Thur', 'Thur', 'Thur', 'Thur'], weekDays: [ '04', '11', '18', '25'], weekStatus: 'Available +', className: 'March' }, { weekMonth: 'April', weekDayofWeek:

问题 I have an array of object, with each object having an imageUrl property, but when I loop through this array to display all images, the image doesn't get rendered I loop through the array and pass the attribute housing the image link to the image src const ProjectData = [ { title: "RestaurantX", imageUrl: "../assets/images/restaurantpassport.png", githubUrl: "", deployUrl: "", description: "", tech: [] }, ] {ProjectData.map(project => { return ( <Work borderColor={changeColor()}> <img src=

问题 I have this code and my question is why inside my answer function I get the initialState. How to set the state in a proper way to get the right one inside a callback of setTimeout function? const App = () => { const [state, setState] = useState({ name: "", password: "", }); useEffect(() => { setState({ ...state, password: "hello" }); setTimeout(answer, 1000); }, []); const answer = () => { console.log(state); // we get initial State }; return <div className="App"></div>; }; 回答1: The reason is

问题 I have an array of object, with each object having an imageUrl property, but when I loop through this array to display all images, the image doesn't get rendered I loop through the array and pass the attribute housing the image link to the image src const ProjectData = [ { title: "RestaurantX", imageUrl: "../assets/images/restaurantpassport.png", githubUrl: "", deployUrl: "", description: "", tech: [] }, ] {ProjectData.map(project => { return ( <Work borderColor={changeColor()}> <img src=

问题 I use formik and react-router-dom for my react login management. However, if click the submit button multiple times in a short time, after redirect to home page, there will be an error of "Warning: Can't perform a React state update on an unmounted component. This is a no-op, but it indicates a memory leak in your application. To fix, cancel all subscriptions and asynchronous tasks in the componentWillUnmount method. in SignInForm (created by Route) in Route (at App.js:52)" And the home page

问题 Is it possible to style Material-UI without using the makeStyles feature, for example, css? Just trying to understand how Material-UI style works. The red style on the bottom is the style I'm trying to achieve with simple css here. 回答1: Below is an example of how to customize the various colors in an outlined select using simple CSS. styles.css .customSelect { width: 200px; } .customSelect .MuiInputLabel-root { color: red; } .customSelect .MuiInputBase-input { color: green; } .customSelect