Related
In my component below, the input field loses focus after typing a character. While using Chrome's Inspector, it looks like the whole form is being re-rendered instead of just the value attribute of the input field when typing.
I get no errors from either eslint nor Chrome Inspector.
Submitting the form itself works as does the actual input field when it is located either in the render's return or while being imported as a separate component but not in how I have it coded below.
Why is this so?
Main Page Component
import React, { Component, PropTypes } from 'react';
import { connect } from 'react-redux';
import { bindActionCreators } from 'redux';
import * as actionPost from '../redux/action/actionPost';
import InputText from './form/InputText';
import InputSubmit from './form/InputSubmit';
class _PostSingle extends Component {
constructor(props, context) {
super(props, context);
this.state = {
post: {
title: '',
},
};
this.onChange = this.onChange.bind(this);
this.onSubmit = this.onSubmit.bind(this);
}
onChange(event) {
this.setState({
post: {
title: event.target.value,
},
});
}
onSubmit(event) {
event.preventDefault();
this.props.actions.postCreate(this.state.post);
this.setState({
post: {
title: '',
},
});
}
render() {
const onChange = this.onChange;
const onSubmit = this.onSubmit;
const valueTitle = this.state.post.title;
const FormPostSingle = () => (
<form onSubmit={onSubmit}>
<InputText name="title" label="Title" placeholder="Enter a title" onChange={onChange} value={valueTitle} />
<InputSubmit name="Save" />
</form>
);
return (
<main id="main" role="main">
<div className="container-fluid">
<FormPostSingle />
</div>
</main>
);
}
}
_PostSingle.propTypes = {
actions: PropTypes.objectOf(PropTypes.func).isRequired,
};
function mapStateToProps(state) {
return {
posts: state.posts,
};
}
function mapDispatchToProps(dispatch) {
return {
actions: bindActionCreators(actionPost, dispatch),
};
}
export default connect(mapStateToProps, mapDispatchToProps)(_PostSingle);
Text Input Component
import React, { PropTypes } from 'react';
const InputText = ({ name, label, placeholder, onChange, value, error }) => {
const fieldClass = 'form-control input-lg';
let wrapperClass = 'form-group';
if (error && error.length > 0) {
wrapperClass += ' has-error';
}
return (
<div className={wrapperClass}>
<label htmlFor={name} className="sr-only">{label}</label>
<input type="text" id={name} name={name} placeholder={placeholder} onChange={onChange} value={value} className={fieldClass} />
{error &&
<div className="alert alert-danger">{error}</div>
}
</div>
);
};
InputText.propTypes = {
name: PropTypes.string.isRequired,
label: PropTypes.string.isRequired,
placeholder: PropTypes.string.isRequired,
onChange: PropTypes.func.isRequired,
value: PropTypes.string,
error: PropTypes.string,
};
InputText.defaultProps = {
value: null,
error: null,
};
export default InputText;
Submit Button Component
import React, { PropTypes } from 'react';
const InputSubmit = ({ name }) => {
const fieldClass = 'btn btn-primary btn-lg';
return (
<input type="submit" value={name} className={fieldClass} />
);
};
InputSubmit.propTypes = {
name: PropTypes.string,
};
InputSubmit.defaultProps = {
name: 'Submit',
};
export default InputSubmit;
it is because you are rendering the form in a function inside render().
Every time your state/prop change, the function returns a new form. it caused you to lose focus.
Try putting what's inside the function into your render directly.
<main id="main" role="main">
<div className="container-fluid">
<FormPostSingle />
</div>
</main>
===>
<main id="main" role="main">
<div className="container-fluid">
<form onSubmit={onSubmit}>
<InputText name="title" label="Title" placeholder="Enter a title" onChange={onChange} value={valueTitle} />
<InputSubmit name="Save" />
</form>
</div>
</main>
This happened to me although I had keys set!
Here's why:
I was using a key from a text field. Inside the same block; I had an input field to update the value of the same text field. Now, since component keys are changing, react re-renders the UI. Hence loosing focus.
What to take from this:
Don't use keys which are constantly changing.
What's happening is this:
When your onChange event fires, the callback calls setState with the new title value, which gets passed to your text field as a prop. At that point, React renders a new component, which is why you lose focus.
My first suggestion would be to provide your components keys, particularly the form and the input itself. Keys allow React to retain the identity of components through renders.
Edit:
See this documentation on keys: https://reactjs.org/docs/lists-and-keys.html#keys
Example:
<TextField
key="password" // <= this is the solution to prevent re-render
label="eMail"
value={email}
variant="outlined"
onChange={(e) => setEmail(e.target.value)}
/>
Had the same issue and solved it in a quick & easy manner: just calling the component with {compName()} instead of <compName />
For instance, if we had:
const foo = ({param1}) => {
// do your stuff
return (
<input type='text' onChange={onChange} value={value} />
);
};
const main = () => (
<foo param1={true} />
);
Then, we just need to change the way we call the foo() component:
const main = () => (
{foo({param1: true})}
);
By adding
autoFocus="autoFocus"
in the input worked for me
<input
type="text"
autoFocus="autoFocus"
value = {searchString}
onChange = {handleChange}
/>
You have to use a unique key for the input component.
<input key="random1" type="text" name="displayName" />
The key="random1" cannot be randomly generated.
For example,
<div key={uuid()} className='scp-ren-row'>
uuid() will generate a new set of string for each rerender. This will cause the input to lose focus.
If the elements are generated within a .map() function, use the index to be part of the key.
{rens.map((ren,i)=>{
return(
<div key={`ren${i+1}`} className='scp-ren-row'>
{ren}{i}
</div>)
}
This will solve the issue.
I also had this problem, my problem was related to using another component to wrap the textarea.
// example with this problem
import React from 'react'
const InputMulti = (props) => {
const Label = ({ label, children }) => (
<div>
<label>{label}</label>
{ children }
</div>
)
return (
<Label label={props.label}>
<textarea
value={props.value}
onChange={e => props.onChange(e.target.value)}
/>
</Label>
)
}
export default InputMulti
when the state changed, react would render the InputMulti component which would redefine the Label component every time, meaning the output would be structurally the same, but because of JS, the function would be considered !=.
My solution was to move the Label component outside of the InputMulti component so that it would be static.
// fixed example
import React from 'react'
const Label = ({ label, children }) => (
<div>
<label>{label}</label>
{ children }
</div>
)
const InputMulti = (props) => {
return (
<Label label={props.label}>
<textarea
value={props.value}
onChange={e => props.onChange(e.target.value)}
/>
</Label>
)
}
export default InputMulti
I've noticed that people often place locally used components inside the component that wants to use it. Usually to take advantage of function scope and gain access to the parent component props.
const ParentComp = ({ children, scopedValue }) => {
const ScopedComp = () => (<div>{ scopedValue }</div>)
return <ScopedComp />
}
I never really thought of why that would be needed, since you could just prop-drill the props to the internal function and externalise it from the parent comp.
This problem is a perfect example of why you should always externalise your components from each other, even if they are used in one module. Plus you can always use smart folder structures to keep things close by.
src/
components/
ParentComp/
ParentComp.js
components/
ScopedComp.js
I had a similar issue when using styled-components inside a functional component. The custom input element was losing focus every time I typed a character.
After much searching and experimenting with the code, I found that the styled-components inside the functional component was making the input field re-render every time I typed a character as the template literal syntax made the form a function although it looks like an expression inside Devtools. The comment from #HenryMueller was instrumental in making me think in the right direction.
I moved the styled components outside my functional component, and everything now works fine.
import React, { useState } from "react";
import styled from "styled-components";
const StyledDiv = styled.div`
margin: 0 auto;
padding-left: 15px;
padding-right: 15px;
width: 100%;
`;
const StyledForm = styled.form`
margin: 20px 0 10px;
`;
const FormInput = styled.input`
outline: none;
border: 0;
padding: 0 0 15px 0;
width: 100%;
height: 50px;
font-family: inherit;
font-size: 1.5rem;
font-weight: 300;
color: #fff;
background: transparent;
-webkit-font-smoothing: antialiased;
`;
const MyForm = () => {
const [value, setValue] = useState<string>("");
const handleChange = (e: React.ChangeEvent<HTMLInputElement>) => {
setValue(e.target.value);
}
const handleSubmit = (e: React.FormEvent) => {
e.preventDefault();
if(value.trim() === '') {
return;
}
localStorage.setItem(new Date().getTime().toString(), JSON.stringify(value));
setValue('');
}
return (
<StyledDiv>
<StyledForm onSubmit={handleSubmit}>
<FormInput type="text"
id="inputText"
name="inputText"
placeholder="What Do You Want To Do Next?"
value={value}
onChange={handleChange}/>
</StyledForm>
</StyledDiv>
)
}
export default MyForm;
The best way to use styled-components in cases like this would be to save them in separate files and import them.
My issue was it was rerendering in a stateless component in the same file. So once I got rid of that unecessary stateless component and just put the code in directly, I didn't have unecessary rerenders
render(){
const NewSocialPost = () =>
<div className='new-post'>
<input
onChange={(e) => this.setState({ newSocialPost: e.target.value })}
value={this.state.newSocialPost}/>
<button onClick={() => this._handleNewSocialPost()}>Submit</button>
</div>
return (
<div id='social-post-page'>
<div className='post-column'>
<div className='posts'>
<Stuff />
</div>
<NewSocialPost />
</div>
<MoreStuff />
</div>
I'm new to React, and have been running into this issue.
Here's what I did to solve:
First move all of your components into your components folder and then import them where you want to use them
Make sure all of your form elements get a name and id property
Make sure all components as you walk up the tree get a unique key
Someone smarter than me can probably tell us why we can skip step one and keep everything inline so to speak, but this just helped me organize the code.
I think the real issue is React is rerendering everything (as already stated) and sometimes that rerender is happening on a parent component that doesn't have a key but needs one.
My problem was with ExpansionPanel components wrapping my custom components for form inputs. The panels needed key as well!
Hope this helps someone else out there, this was driving me crazy!
Basically create a ref and assign it to the input element
const inputRef = useRef(null); // Javascript
const inputRef = useRef<HTMLInputElement>(null); // Typescript
// In your Input Element use ref and add autofocus
<input ref={inputRef} autoFocus={inputRef.current === document.activeElement} {...restProps} />
This will keep the input element in focus when typing.
The problem is with dynamic render() caused by useState() function so you can do this for example.
in this code you should use onChange() to get just the new updated data and onMouseLeave() to handle the update but with condition that data is changed to get better performance
example child
export default function Child(){
const [dataC,setDataC]=useState()
return(<Grid>
<TextField
.
.
onChange={(r)=> setDataC(r.target.value) }
onMouseLeave={(e)=> {
if(dataC!=props.data) { // to avoid call handleupdate each time you leave the textfield
props.handlechange(e.target.value) // update partent.data
}
}
/>
</Grid>)
}
exmple parent
export default function Parent(){
const [data,setData]=useState()
return(
<Grid>
<Child handlechange={handlechanges} data={data}/>
</Grid>)
}
I was facing the same issue, as soon as I type any character, it was losing focus. adding autoFocus props helped me to resolve this issue.
TypeScript Code Snippet
Solution -
Add a unique key to the input element because it helps React to identify which item has changed(Reconciliation). Ensure that your key should not change, it has to be constant as well as unique.
If you are defining a styled component inside a react component. If your input element is inside that styled component then define that styled component outside the input's component. Otherwise, on each state change of the main component, it will re-render your styled component and input as well and it will lose focus.
import React, { useState } from "react";
import styled from "styled-components";
const Container = styled.div`
padding: 1rem 0.5rem;
border: 1px solid #000;
`;
function ExampleComponent() {
// Container styled component should not be inside this ExampleComponent
const [userName, setUserName] = useState("");
const handleInputChange = event => {
setUserName(event.target.value);
};
return (
<React.Fragment>
<Container> {/* Styled component */}
<input
key="user_name_key" // Unique and constant key
type="text"
value={userName}
onChange={handleInputChange}
/>
</Container>
</React.Fragment>
);
}
export default ExampleComponent;
In my case, I had this on a child,
//in fact is a constant
const RenderOnDelete=()=>(
<> .
.
<InputText/>
.
.
</>
)
//is a function that return a constant
const RenderOnRadioSelected=()=>{
switch (selectedRadio) {
case RADIO_VAL_EXIST:
return <RenderOnExist/>
case RADIO_VAL_NEW:
return <RenderOnNew/>
case RADIO_VAL_DELETE:
return <RenderOnDelete/>
default:
return <div>Error</div>
}
}
and this in the parent
return(
<>
.
<RenderOnRadioSelected/>
.
</>
)
Y solved it by not calling a component but a function() or a constant, depending on the case.
.
.
.
//in fact is a constant
const RenderOnDelete=(
<> .
.
<InputText/>
.
.
</>
)
//is a function that return a constant
const RenderOnRadioSelected=()=>{
switch (selectedRadio) {
case RADIO_VAL_EXIST:
return {RenderOnExist}
case RADIO_VAL_NEW:
return {RenderOnNew}
case RADIO_VAL_DELETE:
return {RenderOnDelete}//Calling the constant
default:
return <div>Error</div>
}
}
and this in the parent
return(
<>
.
{RenderOnRadioSelected()}//Calling the function but not as a component
.
</>
)
Adding yet another answer: This happened to me when returning a higher order component inside another component. Eg instead of:
/* A function that makes a higher order component */
const makeMyAwesomeHocComponent = <P, >(Component: React.FC<P>) => {
const AwesomeComponent: React.FC<P & AwesomeProp> = (props) => {
const { awesomeThing, ...passThroughProps } = props;
return (
<strong>Look at: {awesomeThing}!</strong>
<Component {...passThroughProps} />
);
}
return AwesomeComponent;
}
/* The form we want to render */
const MyForm: React.FC<{}> = (props) => {
const MyAwesomeComponent: React.FC<TextInputProps & AwesomeProp> =
makeMyAwesomeHocComponent(TextInput);
return <MyAwesomeComponent awesomeThing={"cat"} onChange={() => { /* whatever */ }} />
}
Move the call to create the higher order component out of the thing you're rendering.
const makeMyAwesomeHocComponent = <P, >(Component: React.FC<P>) => {
const AwesomeComponent: React.FC<P & AwesomeProp> = (props) => {
const { awesomeThing, ...passThroughProps } = props;
return (
<strong>Look at: {awesomeThing}!</strong>
<Component {...passThroughProps} />
);
}
return AwesomeComponent;
}
/* We moved this declaration */
const MyAwesomeComponent: React.FC<TextInputProps & AwesomeProp> =
makeMyAwesomeHocComponent(TextInput);
/* The form we want to render */
const MyForm: React.FC<{}> = (props) => {
return <MyAwesomeComponent awesomeThing={"cat"} onChange={() => { /* whatever */ }} />
}
Solution for this problem is to use useCallback It is used to memoize functions which means it caches the return value of a function given a set of input parameters.
const InputForm = useCallback(({ label, lablevalue, placeholder, type, value,setValue }) => {
return (
<input
key={label}
type={type}
value={value}
onChange={(e) => setIpValue(e.target.value)}
placeholder={placeholder}
/>
);
},[]);
Hope it will solve your problem
If you happen to be developing atomic components for your app's design system, you may run into this issue.
Consider the following Input component:
export const Input = forwardRef(function Input(
props: InputProps,
ref: ForwardedRef<HTMLInputElement>,
) {
const InputElement = () => (
<input ref={ref} {...props} />
);
if (props.icon) {
return (
<span className="relative">
<span className="absolute inset-y-0 left-0 flex items-center pl-2">
<label htmlFor={props.id} className="p-1 cursor-pointer">
{icon}
</label>
</span>
<InputElement />
</span>
);
} else {
return <InputElement />;
}
});
It might seem like a simple optimization at first to reuse your input element across both branches of your conditional render. However, anytime the parent of this component re-renders, this component re-renders, and when react sees <InputElement /> in the tree, it's going to render a new <input> element too, and thus, the existing one will lose focus.
Your options are
memoize the component using useMemo
duplicate some code and define the <input> element in both branches of the conditional render. in this case, it's okay since the <input> element is relatively simple. more complex components may need option 1
so your code then becomes:
export const Input = forwardRef(function Input(
props: InputProps,
ref: ForwardedRef<HTMLInputElement>,
) {
if (props.icon) {
return (
<span className="relative">
<span className="absolute inset-y-0 left-0 flex items-center pl-2">
<label htmlFor={props.id} className="p-1 cursor-pointer">
{icon}
</label>
</span>
<input ref={ref} {...props} />
</span>
);
} else {
return <input ref={ref} {...props} />;
}
});
I did the following steps:
Move dynamic component outside a function
Wrap with useMemo function
const getComponent = (step) =>
dynamic(() => import(`#/components/Forms/Register/Step-${step}`), {
ssr: false,
});
And call this function inside the component by wrapping useMemo:
const CurrentStep = useMemo(() => getComponent(currentStep), currentStep]);
I'm very late but I have been tracking down this issue for days now and finally fixed it. I hope it helps someone.
I'm using Material-ui's Dialog component, and I wanted the dialog to show when a menu item was clicked. Something like so:
import React, { useState } from "react";
import {
Menu,
MenuItem,
Dialog,
DialogContent,
TextField,
} from "#mui/material";
const MyMenu = () => {
const [open, setOpen] = useState(false);
return (
<Menu>
<MenuItem>option 1</MenuItem>
<MenuItem onClick={() => setOpen(!open)}>
option 2
<Dialog open={open}>
<DialogContent>
<TextField />
</DialogContent>
</Dialog>
</MenuItem>
</Menu>
);
};
I was having issues with the TextField losing focus, but only when hitting the a, s, d, c and v keys. If I hit any one of those keys, it would not type anything in the textfield and just lose focus. My assumption upon fixing the issue was that some of the menu options contained those characters, and it would try to switch focus to one of those options.
The solution I found was to move the dialog outside of the Menu component:
const MyMenu = () => {
const [open, setOpen] = useState(false);
return (
<>
<Menu>
<MenuItem>option 1</MenuItem>
<MenuItem onClick={() => setOpen(!open)}>
option 2
</MenuItem>
</Menu>
<Dialog open={open}>
<DialogContent>
<TextField />
</DialogContent>
</Dialog>
</>
);
};
I am unable to find anyone with my specific issue online, and this was the post that came up at the top in my searches so I wanted to leave this here. Cheers
I am not authorised to comment then it must be an answer. I had similar issue and Answer from Alex Yan was corect.
Namely I had that function
const DisplaySearchArea =()=>{return (arrayOfSearchFieldNames.map((element, index)=>{return(<div key ={index} className = {inputFieldStyle}><input placeholder= {arrayOfPlaceholders[index]} type="text" className='border-0'
value={this.state[element]}
onChange={e => {this.setState({ [element]: e.target.value }); console.log(e.target)}}
onMouseEnter={e=>e.target.focus()}/></div>)}))}
that behaves OK with FF and not with Chrome when rendered as <DisplaySearchArea />
When render as {...} it's OK with both. That is not so 'beaty' looking code but working, I have already been told to have tendency to overuse lambdas.
Thanks, Alex. This way I solved my issue:
constructor(props, context) {
...
this.FormPostSingle = this.FormPostSingle.bind(this);
}
FormPostSingle() {
const onChange = this.onChange;
const onSubmit = this.onSubmit;
const valueTitle = this.state.post.title;
return (
<form onSubmit={onSubmit}>
<InputText name="title" label="Title" placeholder="Enter a title" onChange={onChange} value={valueTitle} />
<InputSubmit name="Save" />
</form> );
}
render() {
let FormPostSingle = this.FormPostSingle
return...
}
set the correct id, make sure no other component has same id, set it unique, and it should not change on state update, most common mistake is updating the id with changed value on state update
I had this issue, it was being cause by react-bootstrap/Container, once I got rid of it, included a unique key for every form element, everything worked fine.
For the ones on React Native facing the issue where the text input goes out of focus after typing in single character.
try to pass your onChangeText to your TextInput component.
eg:
const [value, setValue] = useState("")
const onChangeText = (text) => {
setValue(text)
}
return <TextInput value={value} onChangeText={onChangeText} />
This is a great question, and I had the same problem which was 3 parts.
RandomGenerated keys.
Wrong event type.
wrong react JSX attribute.
Keys: when you use random keys each rerender causes react to lose focus (key={Math.random()*36.4621596072}).
EventTypes: onChange cause a rerender with each key stroke, but this can also cause problems. onBlur is better because it updates after you click outside the input. An input, unless you want to "bind" it to something on the screen (visual builders), should use the onBlur event.
Attributes: JSX is not HTML and has it's own attributes (className,...).
Instead of using value, it is better to use defaultValue={foo} in an input.
once I changes these 3 things it worked great. Example below.
Parent:
const [near, setNear] = useState( "" );
const [location, setLocation] = useState( "" );
<ExperienceFormWhere
slug={slug}
questionWhere={question_where}
setLocation={handleChangeSetLocation}
locationState={location}
setNear={setNear}
nearState={near}
key={36.4621596072}/>
Child:
<input
defaultValue={locationState}
className={slug+"_question_where_select search_a_location"}
onBlur={event => setLocation(event.target.value)}/>
I did it with a useRef on input and useEffect
For me this was happening inside Material UI Tabs. I had a search input filter which filtered the table records below it. The search input and table were inside the Tab and whenever a character was typed the input would lose focus (for the obvious reason of re render, the whole stuff inside a tab).
I used the useRef hook for input field ref and then inside my useEffect I triggered the input's focuswhenever the datalist changed. See the code below
const searchInput = useRef();
useEffect(() => {
searchInput.current.focus();
}, [successfulorderReport]);
If working with multiple fields ā and they have to be added and removed dynamically for whatever reason ā you can use autofocus. You have to keep track of the focus yourself, though. More or less like this:
focusedElement = document.activeElement.id;
[ā¦]
const id = 'dynamicField123'; // dynamically created.
<Input id={id} key={id} {...(focusedElement === id ? { autoFocus: true } : {})} />
This issue got me for a second. Since I was using Material UI, I tried to customize one of the wrapper components of my form using the styled() API from material UI. The issue was caused due to defining the DOM customization function inside my render function body. When I removed it from the function body, it worked like a charm. So my inspection is, whenever I updated the state, it obviously tried to refresh the DOM tree and redeclare the styled() function which is inside the render body, which gave us a whole new reference to the DOM element for that wrapper, resulting in a loss of focus on that element. This is just my speculation, please enlighten me if I am wrong.
So removing the styled() implementation away from the render function body solved the issue for me.
This is silly, but... are you (reader, not OP) setting disabled={true} ever?
This is a silly contribution, but I had a problem very much like the one this page is talking about. I had a <textarea> element inside a component that would lose focus when a debounce function concluded.
Well, I realized I was on the wrong track. I was setting the <textarea> to disabled={true} whenever an auto-save function was firing because I didn't want to let the user edit the input while their work was being saved.
When a <textarea> is set to be disabled it will lose focus no matter what trick you try shared here.
I realized there was zero harm in letting the user continue to edit their input while the save was occurring, so I removed it.
Just in case anyone else is doing this same thing, well, that might be your problem. š
Even a senior engineer with 5 years of React experience can do things that dumb.
I have built a minimal ReactJS component to update the number of likes. All works well but the count does not update when clicked. I tried following several answers but cannot figure out why.
See the code:
import React, {useState} from 'react';
class GiveLikes extends React.Component {
// set the initial value of the likes
state = {likes:0};
// Function is called every time "likes" is clicked
likes_count = (likes) =>{
// Counter state is incremented
this.state({likes: likes+1});
}
render() {
return (
<>
<h2> {this.state.likes} </h2>
<div className="buttons">
<button style={{
fontSize: '60%',
position: 'relative',
top: '20vh',
marginRight: '5px',
backgroundColor: 'green',
borderRadius: '8%',
color: 'white',
}}
onClick={() => this.likes_count}>Likes
</button>
</div>
</>
)
}
}
export default GiveLikes;
The above code will render the following on the web browser. Clicking the "Likes" should update the value of the count, but unfortunately it does not.
Declare a constructor and initialize your state,
Use an arrow function on your likes_count() method
Use this.setState({likes: this.state.likes +1}); instead of this.state({likes: this.state.likes +1});
import React, {useState} from 'react';
class GiveLikes extends React.Component {
constructor(props) {
super(props);
this.state = {likes: 0};
}
likes_count = () => {
this.setState({likes: this.state.likes +1});
}
render() {
return (
<>
<h2> {this.state.likes} </h2>
<div className="buttons">
<button style={{
fontSize: '60%',
position: 'relative',
top: '20vh',
marginRight: '5px',
backgroundColor: 'green',
borderRadius: '8%',
color: 'white',
}}
onClick={this.likes_count}>Likes
</button>
</div>
</>
)
}
}
export default GiveLikes;
Edit:
The summary of this answer is that the state does not exist because there is no constructor for this.state
I believe the answer to be is Props are never to be updated. We are to use them as is. Sounds rigid right? But React has its reasons behind this rule and Iām pretty convinced by their reasoning. The only caveat is, though, that there are situations where we might need to initiate the update of a prop. And we will soon know how.
Consider the following line of code from a parent component:
<MyChild childName={this.state.parentName} />
Now if there is any change of name required, parentName will be changed in the parent and that change will automatically be communicated to the child as is the case with the React mechanism. This setup works in most of the scenarios.
But what if you need to update the prop of the child component, and the knowledge of the change required and the trigger to change it is only known to the child? Considering the ways of React, data can only flow from top-to-bottom i.e., from parent-to-child. So then how are we to communicate to the parent that a change to prop is required?
Answer from the following source: https://www.freecodecamp.org/news/how-to-update-a-components-prop-in-react-js-oh-yes-it-s-possible-f9d26f1c4c6d/
I've only shown the parts you need to read nothing else. Please analyse your code properly next time, this isn't a hard thing to do .
You forgot to call the function -
onClick={() => this.likes_count()}
Also, Instead of passing likes you need to use the data from state and then update it like -
likes_count = () => {
let likes = this.state.likes;
this.setState({ likes: likes + 1 });
};
Add a constructor and initialize this.state otherwise it won't be exists.
What happens is every time you re-render your component (by state or props change) you will re-create the your state again and again with {likes: 0} and it will not work.
Also, you are mixing class component and functional component syntax style, which will lead to more bugs and issues with react and your code.
Moreover, you need to put a function that will be called in onClick but you created a function that returns a function, and it is wrong in your case.
Another issue is to set your likes state using this.setState and not just calling state as a function.
import React from 'react';
class GiveLikes extends React.Component {
constructor(props) {
super(props);
this.state = {likes: 0};
}
likes_count = () => {
this.setState ({likes: this.state.likes +1});
}
render() {
return (
<>
<h2> {this.state.likes} </h2>
<div className="buttons">
<button style={{
fontSize: '60%',
position: 'relative',
top: '20vh',
marginRight: '5px',
backgroundColor: 'green',
borderRadius: '8%',
color: 'white',
}}
onClick={this.likes_count}>Likes
</button>
</div>
</>
)
}
}
export default GiveLikes;
Read about react.
Focus on your first component (look for examples with counters components online).
Don't rush into things without fully understand. React is fun.
What's the react way of setting focus on a particular text field after the component is rendered?
Documentation seems to suggest using refs, e.g:
Set ref="nameInput" on my input field in the render function, and then call:
this.refs.nameInput.getInputDOMNode().focus();
But where should I call this? I've tried a few places but I cannot get it to work.
#Dhiraj's answer is correct, and for convenience you can use the autoFocus prop to have an input automatically focus when mounted:
<input autoFocus name=...
Note that in jsx it's autoFocus (capital F) unlike plain old html which is case-insensitive.
You should do it in componentDidMount and refs callback instead. Something like this
componentDidMount(){
this.nameInput.focus();
}
class App extends React.Component{
componentDidMount(){
this.nameInput.focus();
}
render() {
return(
<div>
<input
defaultValue="Won't focus"
/>
<input
ref={(input) => { this.nameInput = input; }}
defaultValue="will focus"
/>
</div>
);
}
}
ReactDOM.render(<App />, document.getElementById('app'));
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.3.1/react.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.3.1/react-dom.js"></script>
<div id="app"></div>
Focus on mount
If you just want to focus an element when it mounts (initially renders) a simple use of the autoFocus attribute will do.
<input type="text" autoFocus />
Dynamic focus
to control focus dynamically use a general function to hide implementation details from your components.
React 16.8 + Functional component - useFocus hook
const FocusDemo = () => {
const [inputRef, setInputFocus] = useFocus()
return (
<>
<button onClick={setInputFocus} >
Focus
</button>
<input ref={inputRef} />
</>
)
}
const useFocus = () => {
const htmlElRef = useRef(null)
const setFocus = () => {htmlElRef.current && htmlElRef.current.focus()}
return [ htmlElRef, setFocus ]
}
Full Demo
React 16.3 + Class Components - utilizeFocus
class App extends Component {
constructor(props){
super(props)
this.inputFocus = utilizeFocus()
}
render(){
return (
<>
<button onClick={this.inputFocus.setFocus}>
Focus
</button>
<input ref={this.inputFocus.ref}/>
</>
)
}
}
const utilizeFocus = () => {
const ref = React.createRef()
const setFocus = () => {ref.current && ref.current.focus()}
return {setFocus, ref}
}
Full Demo
As of React 0.15, the most concise method is:
<input ref={input => input && input.focus()}/>
If you just want to make autofocus in React, it's simple.
<input autoFocus type="text" />
While if you just want to know where to put that code, answer is in componentDidMount().
v014.3
componentDidMount() {
this.refs.linkInput.focus()
}
In most cases, you can attach a ref to the DOM node and avoid using findDOMNode at all.
Read the API documents here: https://facebook.github.io/react/docs/top-level-api.html#reactdom.finddomnode
React 16.3 added a new convenient way to handle this by creating a ref in component's constructor and use it like below:
class MyForm extends Component {
constructor(props) {
super(props);
this.textInput = React.createRef();
}
componentDidMount() {
this.textInput.current.focus();
}
render() {
return(
<div>
<input ref={this.textInput} />
</div>
);
}
}
For more details about React.createRef, you can check this article in React blog.
Update:
Starting from React 16.8, useRef hook can be used in function components to achieve the same result:
import React, { useEffect, useRef } from 'react';
const MyForm = () => {
const textInput = useRef(null);
useEffect(() => {
textInput.current.focus();
}, []);
return (
<div>
<input ref={textInput} />
</div>
);
};
The React docs now have a section for this. https://facebook.github.io/react/docs/more-about-refs.html#the-ref-callback-attribute
render: function() {
return (
<TextInput
ref={function(input) {
if (input != null) {
input.focus();
}
}} />
);
},
I just ran into this issue and I'm using react 15.0.1 15.0.2 and I'm using ES6 syntax and didn't quite get what I needed from the other answers since v.15 dropped weeks ago and some of the this.refs properties were deprecated and removed.
In general, what I needed was:
Focus the first input (field) element when the component mounts
Focus the first input (field) element with an error (after submit)
I'm using:
React Container/Presentation Component
Redux
React-Router
Focus the First Input Element
I used autoFocus={true} on the first <input /> on the page so that when the component mounts, it will get focus.
Focus the First Input Element with an Error
This took longer and was more convoluted. I'm keeping out code that isn't relevant to the solution for brevity.
Redux Store / State
I need a global state to know if I should set the focus and to disable it when it was set, so I don't keep re-setting focus when the components re-render (I'll be using componentDidUpdate() to check for setting focus.)
This could be designed as you see fit for you application.
{
form: {
resetFocus: false,
}
}
Container Component
The component will need to have the resetfocus property set and a callBack to clear the property if it ends up setting focus on itself.
Also note, I organized my Action Creators into separate files mostly due to my project is fairly large and I wanted to break them up into more manageable chunks.
import { connect } from 'react-redux';
import MyField from '../presentation/MyField';
import ActionCreator from '../actions/action-creators';
function mapStateToProps(state) {
return {
resetFocus: state.form.resetFocus
}
}
function mapDispatchToProps(dispatch) {
return {
clearResetFocus() {
dispatch(ActionCreator.clearResetFocus());
}
}
}
export default connect(mapStateToProps, mapDispatchToProps)(MyField);
Presentation Component
import React, { PropTypes } form 'react';
export default class MyField extends React.Component {
// don't forget to .bind(this)
constructor(props) {
super(props);
this._handleRef = this._handleRef.bind(this);
}
// This is not called on the initial render so
// this._input will be set before this get called
componentDidUpdate() {
if(!this.props.resetFocus) {
return false;
}
if(this.shouldfocus()) {
this._input.focus();
this.props.clearResetFocus();
}
}
// When the component mounts, it will save a
// reference to itself as _input, which we'll
// be able to call in subsequent componentDidUpdate()
// calls if we need to set focus.
_handleRef(c) {
this._input = c;
}
// Whatever logic you need to determine if this
// component should get focus
shouldFocus() {
// ...
}
// pass the _handleRef callback so we can access
// a reference of this element in other component methods
render() {
return (
<input ref={this._handleRef} type="text" />
);
}
}
Myfield.propTypes = {
clearResetFocus: PropTypes.func,
resetFocus: PropTypes.bool
}
Overview
The general idea is that each form field that could have an error and be focused needs to check itself and if it needs to set focus on itself.
There's business logic that needs to happen to determine if the given field is the right field to set focus to. This isn't shown because it will depend on the individual application.
When a form is submitted, that event needs to set the global focus flag resetFocus to true. Then as each component updates itself, it will see that it should check to see if it gets the focus and if it does, dispatch the event to reset focus so other elements don't have to keep checking.
edit
As a side note, I had my business logic in a "utilities" file and I just exported the method and called it within each shouldfocus() method.
Cheers!
This is not longer the best answer. As of v0.13, this.refs may not available until AFTER componentDidMount() runs, in some odd cases.
Just add the autoFocus tag to your input field, as FakeRainBrigand showed above.
Ref. #Dave's comment on #Dhiraj's answer; an alternative is to use the callback functionality of the ref attribute on the element being rendered (after a component first renders):
<input ref={ function(component){ React.findDOMNode(component).focus();} } />
More info
Using React Hooks / Functional components with Typescript, you can use the useRef hook with HTMLInputElement as the generic parameter of useRef:
import React, { useEffect, useRef } from 'react';
export default function MyComponent(): JSX.Element {
const inputReference = useRef<HTMLInputElement>(null);
useEffect(() => {
inputReference.current?.focus();
}, []);
return (
<div>
<input ref={inputReference} />
</div>
);
}
Or if using reactstrap, supply inputReference to innerRef instead of ref:
import React, { useEffect, useRef } from 'react';
import { Input } from 'reactstrap';
export default function MyComponent(): JSX.Element {
const inputReference = useRef<HTMLInputElement>(null);
useEffect(() => {
inputReference.current?.focus();
}, []);
return (
<div>
<Input innerRef={inputReference} />
</div>
);
}
Note that none of these answers worked for me with a material-ui TextField component. Per How to set focus to a materialUI TextField? I had to jump through some hoops to get this to work:
const focusUsernameInputField = input => {
if (input) {
setTimeout(() => {input.focus()}, 100);
}
};
return (
<TextField
hintText="Username"
floatingLabelText="Username"
ref={focusUsernameInputField}
/>
);
This is the proper way, how to autofocus. When you use callback instead of string as ref value, it is automatically called. You got your ref available than without the need of touching the DOM using getDOMNode
render: function() {
return <TextInput ref={(c) => this._input = c} />;
},
componentDidMount: function() {
this._input.focus();
},
You don't need getInputDOMNode?? in this case...
Just simply get the ref and focus() it when component gets mounted -- componentDidMount...
import React from 'react';
import { render } from 'react-dom';
class myApp extends React.Component {
componentDidMount() {
this.nameInput.focus();
}
render() {
return(
<div>
<input ref={input => { this.nameInput = input; }} />
</div>
);
}
}
ReactDOM.render(<myApp />, document.getElementById('root'));
You can put that method call inside the render function. Or inside the life cycle method, componentDidUpdate
I have same problem but I have some animation too, so my colleague suggest to use window.requestAnimationFrame
this is ref attribute of my element:
ref={(input) => {input && window.requestAnimationFrame(()=>{input.focus()})}}
AutoFocus worked best for me. I needed to change some text to an input with that text on double click so this is what I ended up with:
<input autoFocus onFocus={this.setCaretToEnd} value={this.state.editTodo.value} onDoubleClick={this.updateTodoItem} />
NOTE: To fix the issue where React places the caret at the beginning of the text use this method:
setCaretToEnd(event) {
var originalText = event.target.value;
event.target.value = '';
event.target.value = originalText;
}
Found here:
https://coderwall.com/p/0iz_zq/how-to-put-focus-at-the-end-of-an-input-with-react-js
<input type="text" autoFocus />
always try the simple and basic solution first, works for me.
To move focus to a newly created element, you can store the element's ID in the state and use it to set autoFocus. e.g.
export default class DefaultRolesPage extends React.Component {
addRole = ev => {
ev.preventDefault();
const roleKey = this.roleKey++;
this::updateState({
focus: {$set: roleKey},
formData: {
roles: {
$push: [{
id: null,
name: '',
permissions: new Set(),
key: roleKey,
}]
}
}
})
}
render() {
const {formData} = this.state;
return (
<GridForm onSubmit={this.submit}>
{formData.roles.map((role, idx) => (
<GridSection key={role.key}>
<GridRow>
<GridCol>
<label>Role</label>
<TextBox value={role.name} onChange={this.roleName(idx)} autoFocus={role.key === this.state.focus}/>
</GridCol>
</GridRow>
</GridSection>
))}
</GridForm>
)
}
}
This way none of the textboxes get focus on page load (like I want), but when you press the "Add" button to create a new record, then that new record gets focus.
Since autoFocus doesn't "run" again unless the component gets remounted, I don't have to bother unsetting this.state.focus (i.e. it won't keep stealing focus back as I update other states).
Simple solution without autofocus:
<input ref={ref => ref && ref.focus()}
onFocus={(e)=>e.currentTarget.setSelectionRange(e.currentTarget.value.length, e.currentTarget.value.length)}
/>
ref triggers focus, and that triggers onFocus to calculate the end and set the cursor accordingly.
Ben Carp solution in typescript
React 16.8 + Functional component - useFocus hook
export const useFocus = (): [React.MutableRefObject<HTMLInputElement>, VoidFunction] => {
const htmlElRef = React.useRef<HTMLInputElement>(null);
const setFocus = React.useCallback(() => {
if (htmlElRef.current) htmlElRef.current.focus();
}, [htmlElRef]);
return React.useMemo(() => [htmlElRef, setFocus], [htmlElRef, setFocus]);
};
Warning: ReactDOMComponent: Do not access .getDOMNode() of a DOM node; instead, use the node directly. This DOM node was rendered by App.
Should be
componentDidMount: function () {
this.refs.nameInput.focus();
}
The simplest answer is add the ref="some name" in the input text element and call the below function.
componentDidMount(){
this.refs.field_name.focus();
}
// here field_name is ref name.
<input type="text" ref="field_name" />
After trying a lot of options above with no success I've found that It was as I was disabling and then enabling the input which caused the focus to be lost.
I had a prop sendingAnswer which would disable the Input while I was polling the backend.
<Input
autoFocus={question}
placeholder={
gettingQuestion ? 'Loading...' : 'Type your answer here...'
}
value={answer}
onChange={event => dispatch(updateAnswer(event.target.value))}
type="text"
autocomplete="off"
name="answer"
// disabled={sendingAnswer} <-- Causing focus to be lost.
/>
Once I removed the disabled prop everything started working again.
Read almost all the answer but didnt see a getRenderedComponent().props.input
Set your text input refs
this.refs.username.getRenderedComponent().props.input.onChange('');
According to the updated syntax, you can use this.myRref.current.focus()
Focus using createRef for functional components
To developers using Functional Components. This seems to suit. Focus happens on inputfield after clicking on the button. I've attached CodeSandbox link too.
import React from 'react';
export default function App() {
const inputRef = React.createRef();
return <>
<input ref={inputRef} type={'text'} />
<button onClick={() => {if (inputRef.current) { inputRef.current.focus() }}} >
Click Here
</button>
</>
}
https://codesandbox.io/s/blazing-http-hfwp9t
That one worked for me:
<input autoFocus={true} />
Updated version you can check here
componentDidMount() {
// Focus to the input as html5 autofocus
this.inputRef.focus();
}
render() {
return <input type="text" ref={(input) => { this.inputRef = input }} />
})
Since there is a lot of reasons for this error I thought that I would also post the problem I was facing. For me, problem was that I rendered my inputs as content of another component.
export default ({ Content }) => {
return (
<div className="container-fluid main_container">
<div className="row">
<div className="col-sm-12 h-100">
<Content /> // I rendered my inputs here
</div>
</div>
</div>
);
}
This is the way I called the above component:
<Component Content={() => {
return (
<input type="text"/>
);
}} />
I'm using this React component to upload files to the browser (not to a server). This component is part of the react-jsonschema-form library, so I can't change the source code. The render method of this component is shown below
render() {
const { multiple, id, readonly, disabled, autofocus } = this.props;
const { filesInfo } = this.state;
return (
<div>
<p>
<input
ref={ref => (this.inputRef = ref)}
id={id}
type="file"
disabled={readonly || disabled}
onChange={this.onChange}
defaultValue=""
autoFocus={autofocus}
multiple={multiple}
/>
</p>
<FilesInfo filesInfo={filesInfo} />
</div>
);
}
This component accepts one or more files as input, base64 encodes them, and stores the encoded files in memory.
However, if the user chooses a large file (e.g. 5MB), there's a noticeable delay while processing. I would like to show a spinner when this processing starts and hide it when it finishes, but I can't find the relevant events on which to show/hide the spinner.
In case it's relevant, I have a ref to the widget, and can use this to get a ref to the <input> field via myWidgetRef.inputRef.
You can add the change event listener to the input ref, which will be called when a file is selected.
onChange function passed as a prop is only called when the upload is finished
Then use the onChange prop for handling processing completion.
import React from "react";
import { render } from "react-dom";
import Form from "react-jsonschema-form";
import FileWidget from "react-jsonschema-form/lib/components/widgets/FileWidget";
class MyForm extends React.Component {
constructor(props) {
super(props);
this.state = {
processing: false
};
this.inputChanged = this.inputChanged.bind(this);
}
inputChanged() {
console.log("processing");
this.setState({ processing: true });
}
componentDidMount() {
this.fileWidget.inputRef.addEventListener("change", this.inputChanged);
}
componentWillUnmount() {
this.fileWidget.inputRef.removeEventListener("change", this.inputChanged);
}
render() {
return (
<React.Fragment>
<div>Is processing: {this.state.processing + ""}</div>
<Form
schema={{
type: "object",
properties: {
file: {
type: "string",
format: "data-url"
}
}
}}
widgets={{
FileWidget: props => (
<FileWidget
{...props}
ref={ref => {
this.fileWidget = ref;
}}
onChange={() => {
console.log("processed");
this.setState({ processing: false });
}}
/>
)
}}
liveValidate
/>
</React.Fragment>
);
}
}
render(<MyForm />, document.getElementById("root"));
onChange = () => {
this.setState({uploading: true})
//upload fetch call
fetch().then(results => {//this is dummy call
this.setState({uploading: false})
})
}
render() {
const { multiple, id, readonly, disabled, autofocus } = this.props;
const { filesInfo } = this.state;
return (
<div>
<p>
{this.state.uploading ? <div className="progress"></div> : null}
<input
ref={ref => (this.inputRef = ref)}
id={id}
type="file"
disabled={readonly || disabled}
onChange={this.onChange}
defaultValue=""
autoFocus={autofocus}
multiple={multiple}
/>
</p>
<FilesInfo filesInfo={filesInfo} />
</div>
);
}
As far as I understand you're processing this large file on client side.
So the simpliest solution for you will be to put loading flag before processing start and remove it after processing ends.
After you do this - you will encounter that flag change doesn't reflected to DOM state, because rendering is deferred.
So the solution will be to convert code from:
setLoadingFlag();
doComputing();
removeLoadingFlag();
to async form:
setLoadingFlag();
setTimeout(() => {
doComputing();
removeLoadingFlag();
}, 0)
This will allow React to render loader
What you can do is:
Use axios in react to also show percentage of file loading.
Create a simple html absolute loader with two styles of the element one will contain css:
display: block;
Another will contain:
display: none;
Give your loader element classname and change it with this.state so when you start uploading file you will change classname of loader element to one which contains styling of display block , then change it back to prvious when uploading done.
If you want full code drop me a message i have one.
Rohan Girdhani
simplest way of doing this is got to main.html(the file which has your main container) and add an additional div like this. Note that this div is noting but an hcl css version of the spinner
<div class ="app-spinner" style="display: none" />
Note that by default the spinner is hidden (display: none); Now define an utility method which will toggle spinner on and off. something like this
`
export const showLoader = (load) => {
load ? document.getElementsByClassName("app-spinner").style.display="block" : document.getElementsByClassName("app-spinner").style.display="none"
}
`
now all you have to do is import showLoader in the file whre you have input type file like this
`
import { showLoader } from "../pathWhereTheUtilityMethodIsDeclared"
`
Now go to the Input tag and add an onClick event and trigger the utility method like this Note we are not using onChange
<input
ref={ref => (this.inputRef = ref)}
id={id}
type="file"
disabled={readonly || disabled}
onChange={this.onChange}
onClick={()=>{showLoader(true)}}
defaultValue=""
autoFocus={autofocus}
multiple={multiple}
/>
onClick={()=>{showLoader(true)}} will toggle on the hidden spinner and when the encoding to base64 is done just call the method with false showLoader(false) this will make sure that spinner is hidden. (Note make sure u import showloader before calling else u end up with undefined error)
I had a <div> with a <p> child component I name SocialPostwithCSS, and onClick would cause it to hide, change the state to editing: true and a <textarea> would show up and I would use this.textarea.focus with the textarea having ref={(input)=>{this.textarea=input}} and had no problem.
I needed to autosize the area, so I downloaded the NPM package TextareaAutosize, now I'm having issues focusing on this text area. I check, the npm TextareAutosize file has class and is not stateless. Currently this.textarea is returning undefined
Summary: How can I focus on <TextareaAutosize /> after <div> onClick
which causes the state change to show <TextareaAutosize>?
File Below:
import React, { Component } from 'react'
import SocialPostWithCSS from './SocialPostWithCSS'
import TextareaAutosize from 'react-autosize-textarea'
class SocialPost extends Component {
constructor(props) {
super(props)
this.state = {
message: this.props.socialPost.message,
editing: false
}
}
_clickToEdit() {
this.textarea.focus()
}
render() {
return (
<div>
{(!this.state.editing) ?
<div onClick={async ()=>{await this.setState({editing: true});this._clickToEdit}}>
<SocialPostWithCSS >{this.state.message}</SocialPostWithCSS>
</div>
:<div>
<TextareaAutosize
onBlur={() => {this.setState({ editing: false})}}
type='text'
ref={(input)=>{this.textarea=input}}
value={this.state.message}
/>
</div>
}
</div>
)
}
}
export default SocialPost
From looking at the code, it appears that TextareaAutosize exposes the inner ref through a prop named innerRef. So change your code like this:
<TextareaAutosize
onBlur={() => {this.setState({ editing: false})}}
type='text'
innerRef={(input)=>{this.textarea=input}}
value={this.state.message}
/>
this.textarea is returning undefined onclick to the div because initially when this.state.editing is false TextareaAutosize component was not rendered and hence this.textarea was not initialized by the mounted instance of the component.