reactjs

问题 I'm trying to follow a react tutorial, My webpack.config.js file is as follows: var webpack = require("webpack"); var pth = require("path"); module.exports = { entry: "./src/index.js", output: { path: __dirname + "/dist", filename: "bundle.js" }, devServer: { inline: true, contentBase: './dist', port: 3000 }, module: { rules: [ { test: /\.js$/, exclude: /(node_modules)/, use: 'babel-loader' }, { test: /\.json$/, exclude: /(node_modules)/, use: 'json-loader' } ] } } While my Code files are as

问题 I'm trying to follow a react tutorial, My webpack.config.js file is as follows: var webpack = require("webpack"); var pth = require("path"); module.exports = { entry: "./src/index.js", output: { path: __dirname + "/dist", filename: "bundle.js" }, devServer: { inline: true, contentBase: './dist', port: 3000 }, module: { rules: [ { test: /\.js$/, exclude: /(node_modules)/, use: 'babel-loader' }, { test: /\.json$/, exclude: /(node_modules)/, use: 'json-loader' } ] } } While my Code files are as

问题 I’m tying to position a circle in the middle of the component’s root DOM element: var App = React.createClass({ render: function() { return <svg ref="svg"> <circle r="9" cx={this.centerX()} cy="15"/> </svg>; }, centerX: function() { var svg = this.refs.svg.getDOMNode(); return svg.offsetLeft + Math.round(svg.offsetWidth / 2); } }); http://jsfiddle.net/NV/94tCQ/ Chicken-and-egg problem takes place here: this.refs is undefined on the first render. What’s the best way to solve this it? I would

问题 I have an array of objects that contain keypair values for the navbar links, I have mapped the array to list and rendering it successful, but when I try to add class to only active link, it is adding the class to all the link items. Wondering where I am going wrong? import React, { Component } from "react"; import { Link } from "react-router-dom"; class SideNavbar extends Component { constructor(props) { super(props); this.state = [ { id: 1, name: "Link1", to: "/cms", className: "side_nav

问题 In my React based application, there is a rest API call which fetches all the data in one shot which is needed for the whole page. The response has data which can be used in a population of dropdowns as well. But I am not sure how this can be achieved. I am currently making a new request whenever the drop-down value is selected. Please do suggest me how to do implement it efficiently without making multiple unwanted rest calls. 回答1: you can cache in HDD or RAM. HDD = e.g. localStorage RAM =

问题 In my React based application, there is a rest API call which fetches all the data in one shot which is needed for the whole page. The response has data which can be used in a population of dropdowns as well. But I am not sure how this can be achieved. I am currently making a new request whenever the drop-down value is selected. Please do suggest me how to do implement it efficiently without making multiple unwanted rest calls. 回答1: you can cache in HDD or RAM. HDD = e.g. localStorage RAM =

问题 I have a component that has props which extend RouteComponentProps that looks like this: export interface RouteComponentProps<P> { match: match<P>; location: H.Location; history: H.History; staticContext?: any; } Now, when I use my component in the app, I pass these props to it: <MyComponent match={this.props.match} location={this.props.location} history={this.props.history} /> The props are available already because it's running inside react router. Now, how do I test this component without

问题 I have a component that has props which extend RouteComponentProps that looks like this: export interface RouteComponentProps<P> { match: match<P>; location: H.Location; history: H.History; staticContext?: any; } Now, when I use my component in the app, I pass these props to it: <MyComponent match={this.props.match} location={this.props.location} history={this.props.history} /> The props are available already because it's running inside react router. Now, how do I test this component without

问题 I have a component that has props which extend RouteComponentProps that looks like this: export interface RouteComponentProps<P> { match: match<P>; location: H.Location; history: H.History; staticContext?: any; } Now, when I use my component in the app, I pass these props to it: <MyComponent match={this.props.match} location={this.props.location} history={this.props.history} /> The props are available already because it's running inside react router. Now, how do I test this component without

问题 How can I use a React ref as a mutable instance, with Typescript? The current property appears to be typed as read-only. I am using React + Typescript to develop a library that interacts with input fields that are NOT rendered by React. I want to capture a reference to the HTML element and then bind React events to it. const inputRef = useRef<HTMLInputElement>(); const { elementId, handler } = props; // Bind change handler on mount/ unmount useEffect(() => { inputRef.current = document