setstate

问题 I'm still learning React and working on coding John Conway's Game of Life. I have created a game board for the game using a 2D array in state. I have this 2D array stored in state in my App.js . I also have two functional components, Gameboard.js and Square.js receiving props and creating the game board. Gameboard.js creates a table and passed props to Square.js letting it know which squares should be highlighted and which shouldn't. In other words it let's each individual square know if the

问题 I am using react-table for the data-grid purpose. I am implementing a settings icon which shows the list of columns and based on the selection, the column gets shown or hidden. I am manipulating "show" property of columns object for this. While the property is getting set properly, there is no such change in the table. Can someone help me with this. But when I set the property directly(in App component) it works. Where am I going wrong? Code Sandbox: https://codesandbox.io/s/blue-cherry-di3ub

问题 I have a method that calls an addListener to data that does not exist yet until you've clicked on a button. However, as I try to set that data inside a state, I get the following error: TypeError: this.setState is not a function I've tried binding my dataHandler like this: this.dataHandler = this.dataHandler.bind(this) yet it still returns this error. What am I forgetting here? constructor(props){ super(props) this.state = { selActive: 4, loaded: false, mapInfo: '' } this.onScriptLoad = this

问题 I want to know about this in yii: Yii::app()->user->setState('key','value'); If I have a array of size 10 and I set this array in state like: Yii::app()->user->setState('data',$dataArray) I have another array of size 15000 and I set this array in state like: Yii::app()->user->setState('data',$dataArray) Is this Ok? Or It will effect the speed of my Yii project i.e. larger the setState data size ,slower will be the speed of yii project? Is it is secure way for confidential data like Password

问题 I’ve got a very deeply nested object in my React state. The aim is to change a value from a child node. The path to what node should be updated is already solved, and I use helper variables to access this path within my setState. Anyway, I really struggle to do setState within this nested beast. I abstracted this problem in a codepen: https://codesandbox.io/s/dazzling-villani-ddci9 In this example I want to change the child’s changed property of the child having the id def1234 . As mentioned

问题 I send my function to child component for callBack . In the parent, I have a function with setState method: onInputUpdated(id){ var array = {}; let char = id.slice(-1); console.log(this.state.states) switch(char){ case 'a': array[id] = this.getY(ReactDOM.findDOMNode(this.refs[id].refs.inp).value); break; case 'b': array[id] = this.getX(ReactDOM.findDOMNode(this.refs[id].refs.inp).value); break; } let oldStates = this.state.states; oldStates[id] = array[id]; this.setState({ states: oldStates }

问题 Hi I'm new to React so bear with me. I'm want to store geoposition as a state. Seems nifty since any change in position will trigger a render, which is exactly what I want. During development I have a button that manual triggers the event by accessing the lastPosition . But when I do. The state is "undefined". Any clue why? export default class FetchProject extends Component { constructor(props) { super(props); this.state = { initialPosition: 'unknown', lastPosition: 'unknown', }; } //code

问题 I know some react but I am stuck in a weird situation. I have two inputs and a button, the button should be enabled when both inputs are not empty. So, I used a state property for each input value and also one property telling me if both inputs have value: this.state = { title: '', time :'', enabled : false } also I have a onChange for each input to set State accordingly: <input type="text" id="time" name="time" onChange={this.onChange.bind(this)} value={this.state.time}></input> <input type=

问题 I have a component structure like this <A> <B> <C/> <C/> </B> <D> <E/> <E/> </D> </A> Idea is that actions on components in block E are processed by a function of component A to state of A and than passed down to B and C as props. I know, that better way was to use Flux, pubsub-js or other Store-message system, but hope if someone can explain why correct to the best of my understanding solution doesn't work. Calling this function of component A simalteneously from multiple instances of

问题 Background Our webapp is written with React and Redux using the official react-redux bindings. Another primary library used in this web app is PaperJS. We recently transitioned this to being a Redux app, though it has used React for a while. The Problem Refreshing sometimes (usually every other refresh) causes a RangeError: Maximum call stack size exceeded at String.replace (<anonymous>) at Object.unescape (KeyEscapeUtils.js:49) at flattenSingleChildIntoContext (flattenChildren.js:32) at