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How to get selected values from multiple dropdowns on button click using ReactJs

I want to console.log() multiple values from five different dropdowns on a button click. I have done this for one dropdown, but I don't know how to do it for more. I'm still a beginner.
Here's my code:
export default function Suma() {
const typedemande = [
{ value: "first", label: "first" },
{ value: "second", label: "second" },
];
const [message, setMessage] = useState('');
const handleChange = event => {
setMessage(event);
};
const handleClick = event => {
event.preventDefault();
console.log(message);
};
return (
<div>
<div className="col-lg">
<Select placeholder="choose" id="message" className="react-dropdown " name="message" onChange={handleChange}
value={message}
isClearable
isSearchable={false}
classNamePrefix="dropdown"
options={typedemande}
/>
</div>
<div className="text-center">
<button className="mr-2 btn btn-primary" onClick={handleClick}>Click me</button>
</div>
</div>
);
};

I hope you are looking for this one:
export default function App() {
const typedemande = [
{ value: "first", label: "first" },
{ value: "second", label: "second" },
{ value: "third", label: "third" },
{ value: "fourth", label: "fourth" },
{ value: "five", label: "five" },
];
const [showAll, setShowAll ] = useState([]);
const [dropdowns,setDrodowns] = useState({
'message1': '',
'message2': '',
'message3': '',
'message4': '',
'message5': '',
});
const handleChange = (event) => {
setDrodowns({...dropdowns,[event.target.name]:event.target.value});
}
const handleClick = (event) => {
event.preventDefault(); // if you use the element inside `form` then it would prevent to submit
console.log(dropdowns);//to log the values in console
setShowAll(Object.values(dropdowns));// to show the changes in UI
}
return (
<div>
<div className="col-lg">
<Select
name="message1"
onChange={handleChange}
value={"second"}
options={typedemande}
/>
<Select
name="message2"
onChange={handleChange}
value={"second"}
options={typedemande}
/>
<Select
name="message3"
onChange={handleChange}
value={"second"}
options={typedemande}
/>
<Select
name="message4"
onChange={handleChange}
value={"second"}
options={typedemande}
/>
<Select
name="message5"
onChange={handleChange}
value={"second"}
options={typedemande}
/>
</div>
<hr/>
<ul>
{ showAll.map((val,i)=><li key={i}>{i+1} --- {val}</li>) }
</ul>
<hr/>
<div className="text-center">
<button className="mr-2 btn btn-primary" onClick={handleClick}>Click me</button>
</div>
</div>
);
}
For details check the code sandbox link
Out put
Edit: Based on user comments I edited the answer

You could pass a parameter to your handleChange.
const handleChange = (event, position) => {
console.log(position);
};
<Select onChange={(e) => handleChange(e, 1)} />
<Select onChange={(e) => handleChange(e, 2)} />
<Select onChange={(e) => handleChange(e, 3)} />

Improving axtck's answer, you can get each select value like below
import React, {useState} from 'react';
import Select from 'react-select';
export function App(props) {
const typedemande = [
{ value: "first", label: "first" },
{ value: "second", label: "second" },
];
const [messages, setMessages] = useState([]);
const handleChange = (event, pos) => {
console.log(pos)
console.log(event.value)
let mz = [...messages];
if (mz.length > 0 && mz.findIndex(msg => msg.index == pos) > -1) {
mz[mz.findIndex(msg => msg.index == pos)] = event.value;
setMessages(mz);
}
else {
mz.push({
index: pos,
value: event.value
});
setMessages(mz);
}
};
const handleClick = event => {
event.preventDefault();
for (let i = 0; i < messages.length; i++)
console.log(messages[i].value)
};
return (
<div>
<div className="col-lg">
<Select placeholder="choose" id="message" className="react-dropdown " name="message" onChange={(e) => handleChange(e, 1)}
value={messages[0] ? messages[0].label : ''}
isClearable
isSearchable={false}
classNamePrefix="dropdown"
options={typedemande}
/>
<Select placeholder="choose" id="message" className="react-dropdown " name="message" onChange={(e) => handleChange(e, 2)}
value={messages[1] ? messages[1].label : ''}
isClearable
isSearchable={false}
classNamePrefix="dropdown"
options={typedemande}
/>
</div>
<div className="text-center">
<button className="mr-2 btn btn-primary" onClick={handleClick}>Click me</button>
</div>
</div>
);
}

Duplicate value of useRef current value after switching between tabs in react

If i switch between Transfer to Beneficiary and All Beneficiary tab the Select options get duplicated but if i change the second useEffect hook dependency to allBeneficiary.current instead of beneficiaries presently there, Select options doesnt duplicate, but the options are not rendered on the first render until I switch to All Beneficiary tab and back to Transfer Beneficiary
Below is the Transfer to Beneficiary code
// Hooks and Contexts
import React, { useState, useContext, useEffect, useRef } from "react";
import { TransferPointsContext } from "../../../../../context/TransferPoints";
import { LoaderContext } from "../../../../../context/Loading";
// Components
import TransferSummary from "../../../../common/modals/TransferSummary";
import Loading from "../../../../features/Loader/Loading";
// UI
import swal from "sweetalert";
import toastr from "toastr";
import Select from "react-select";
import "./css/transfer-points.css";
import { nanoid }from 'nanoid'
function TransferPoints() {
const [showTransferSummary, setShowTransferSummary] = useState(false);
const [transferSummaryData, setTransferSummaryData] = useState(false);
const [showBeneficiaryDataPage, setShowBeneficiaryDataPage] = useState(false);
const [checked, setChecked] = useState(false);
const [ options, setOptions ] = useState([])
const {
verifyCardNumber,
verifyCardState,
getBeneficiaryList,
beneficiaries, //list of beneficiaries from API
hideBeneficiaryDataPage,
setInputs,
inputs,
} = useContext(TransferPointsContext);
const { loading } = useContext(LoaderContext);
toastr.options.progressBar = true;
toastr.options = {
toastClass: "alert",
iconClasses: {
error: "alert-error",
info: "alert-info",
success: "alert-success",
warning: "alert-warning",
},
};
const allBeneficiaries = useRef([]);
useEffect(() => {
getBeneficiaryList();
}, [allBeneficiaries]);
useEffect(() => {
if (beneficiaries.data !== null) {
if (
beneficiaries.data.status === 0 &&
beneficiaries.data.success === false
) {
toastr.error("Failed to fetch user beneficiaries!", "error", {
iconClass: "toast-error",
});
console.log("beneficiaries", beneficiaries.data);
} else if (
beneficiaries.data.status === 1 &&
beneficiaries.data.success === true
) {
console.log('All beneficiary ', allBeneficiaries.current)
beneficiaries.data.data.forEach((beneficiary) => {
console.log('For each ', beneficiary)
allBeneficiaries.current.unshift({
value: beneficiary.membership_number,
label: `${beneficiary.first_name} ${beneficiary.last_name == null ? '' : beneficiary.last_name}`,
});
});
console.log('LENGTH ', allBeneficiaries.current.length)
}
}
}, [beneficiaries]);
useEffect(() => {
if (hideBeneficiaryDataPage) {
setShowBeneficiaryDataPage(false);
}
}, [hideBeneficiaryDataPage]);
const beneficiaryData = useRef({});
useEffect(() => {
if (verifyCardState.data !== null) {
if (
verifyCardState.data.status === 1 &&
verifyCardState.data.success === true
) {
setShowBeneficiaryDataPage(true);
beneficiaryData.current = {
name: `${verifyCardState.data.data.first_name} ${verifyCardState.data.data.last_name == null ? '' : verifyCardState.data.data.last_name}`,
};
toastr.success("Membership Id Validated!", "Success", {
iconClass: "toast-success",
});
return;
}
if (
verifyCardState.data.status === 0 &&
verifyCardState.data.success === false
) {
if (verifyCardState.data.message && !verifyCardState.data.data) {
toastr.error(verifyCardState.data.message, "Validation failed!", {
iconClass: "toast-error",
});
setShowBeneficiaryDataPage(false);
return;
}
setShowBeneficiaryDataPage(false);
const errorMessages = verifyCardState.data.data;
for (const error in errorMessages) {
toastr.error(errorMessages[error], "Validation Error!", {
iconClass: "toast-error",
});
}
return;
}
}
}, [verifyCardState]);
const handleSearchInput = (event) => {
const card_number = event.value;
setInputs((inputs) => ({
...inputs,
card_number,
}));
verifyCardNumber(card_number);
};
const proceedToTransfer = () => {
const amount = document.getElementById("amount").value;
if (amount.trim().length === 0) {
swal({
title: "Oops!",
text: `Amount field cannot be empty`,
icon: "error",
button: "Ok",
});
return;
}
setShowTransferSummary(!showTransferSummary);
setTransferSummaryData({
amount,
name: beneficiaryData.current.name,
membership_id: inputs.card_number,
save_beneficiary: (beneficiaryData.current.save_beneficiary == 1) ? 1 : 0,
});
};
const handleInputChange = (event) => {
event.persist();
setInputs((inputs) => ({
...inputs,
[event.target.name]: event.target.value,
}));
};
const handleChange = (event) => {
event.persist();
setChecked(event.target.checked);
const save_beneficiary = event.target.checked === true ? 1 : 0;
beneficiaryData.current.save_beneficiary = save_beneficiary;
};
console.log('LENGTH ', allBeneficiaries.current)
// console.log('current beneficiaries ', (allBeneficiaries.current) )
// console.log('CHECKED ', beneficiaryData.current.save_beneficiary )
// let id = nanoid()
return (
<div>
{/* {loading ? <Loading /> : ""} */}
<form action="#">
<div className="row">
<div className="col-md-12">
<div className="form-group">
<label htmlFor="acc-email">Select Beneficiary </label>
<Select
onChange={handleSearchInput}
className="basic-single"
classNamePrefix="select"
isClearable="true"
isSearchable="true"
name="beneficiary_card_number"
defaultValue="Select"
options={allBeneficiaries.current} //THIS RETURNS DUPLICATED VALUE ON NAVIGATING TO ALL BENEFICIARIES AND BACK
/>
</div>
<h6 class="mt-3 heading-border border-0">OR</h6>
<div className="row align-items-center justify-content-between">
<div className="col-md-8">
<label htmlFor="card_number">Enter Membership Id</label>
<input
type="text"
className="form-control"
name="card_number"
onChange={handleInputChange}
value={inputs.card_number}
/>
</div>
<div className=" col-4 " style={{marginTop: '30px', paddingLeft: '10px', textAlign: 'end',}}>
<button
onClick={() => verifyCardNumber(inputs.card_number)}
type="button"
className="btn-lg btn btn-primary"
>
Validate Id
</button>
</div>
</div>
</div>
{showBeneficiaryDataPage === true ? (
<div className="col-sm-12">
<h6 class="mt-3 heading-border border-0"></h6>
<div className="row">
<div className="col-md-6">
<div className="form-group">
<label htmlFor="acc-name">Name</label>
<input
type="text"
className="form-control"
id="acc-name"
required
disabled
name="acc-name"
value={beneficiaryData.current.name}
/>
</div>
</div>
<div className="col-md-6">
<div className="form-group">
<label htmlFor="acc-lastname">Membership Id</label>
<input
type="text"
className="form-control"
id="acc-lastname"
required
disabled
name="acc-lastname"
value={inputs.card_number}
/>
</div>
</div>
</div>
<div className="row">
<div className="col-md-12">
<div className="form-group">
<label htmlFor="acc-lastname">Amount</label>
<input
type="text"
className="form-control"
id="amount"
required
name="amount"
onChange={handleInputChange}
value={inputs.amount}
/>
</div>
</div>
</div>
<div class="form-check">
<input
class="form-check-input"
type="checkbox"
checked={checked}
name="save_beneficiary"
onChange={handleChange}
/>
<span className="ml-3 font-weight-bold terms-condition">
Save Beneficiary
</span>
</div>
<div className="mb-2"></div>
<div className="form-footer">
<div className="col-md-12 d-flex justify-content-center">
<button
onClick={() => proceedToTransfer()}
type="button"
className="btn-lg w-50 btn btn-primary"
>
Proceed
</button>
</div>
</div>
</div>
) : (
""
)}
</div>
</form>
{showTransferSummary === true ? (
<TransferSummary data={transferSummaryData} setShowTransferSummary={setShowTransferSummary} setShowBeneficiaryDataPage={setShowBeneficiaryDataPage}/>
) : (
""
)}
</div>
);
}
export default React.memo(TransferPoints);
This is the code for All Beneficiaries
import React, { useState, useContext, useEffect, useRef } from "react";
import "./css/transfer-points.css";
import { TransferPointsContext } from "../../../../../context/TransferPoints";
import Loading from "../../../../features/Loader/Loading";
import swal from "sweetalert";
import { LoaderContext } from "../../../../../context/Loading";
import toastr from "toastr";
import axios from 'axios'
import { ToastContainer, toast } from 'react-toastify';
function ShowAllBeneficiariesPage() {
const [ data, setData ] = useState([])
const {
getBeneficiaryList,
beneficiaries,
removeBeneficiary,
state,
} = useContext(TransferPointsContext);
const { loading } = useContext(LoaderContext);
toastr.options.progressBar = true;
toastr.options = {
toastClass: "alert",
iconClasses: {
error: "alert-error",
info: "alert-info",
success: "alert-success",
warning: "alert-warning",
},
};
const handleDelete = (id) => {
swal({
title: "Are you sure you want to remove beneficiary?",
text: "You won't be able to revert this!",
icon: "warning",
buttons: ["Cancel", "Proceed!"],
showCancelButton: true,
confirmButtonColor: "#3085d6",
cancelButtonColor: "#d33",
}).then((result) => {
if (result === true) {
removeBeneficiary(id);
console.log('ID OF RECEIVER ', id)
const newBeneficiary = data.filter(add => add.id !== id)
setData(newBeneficiary)
toastr.success("Beneficiary Removed !", "Success", {
iconClass: "toast-success",
});
}
});
};
const fetchData = () => {
axios.get(`user/beneficiaries`)
.then( res => setData(res.data.data ))
}
useEffect(() => {
fetchData()
}, [])
return (
<div>
{/* {loading ? <Loading /> : ""} */}
{ data.length === 0 ?
(
<div style={{textAlign: 'center'}}>No beneficiaries found</div>
)
:
(
<div className="col-sm-12">
{data.map((item) => {
console.log('Beneficiary Data ', data)
return (
<p className="mb-1 p-4 beneficiary-list">
{item.first_name} {item.last_name} - {item.membership_number}
<i
style={{ cursor: "pointer" }}
onClick={() => handleDelete(item.id)}
class="float-right fas fa-trash"
></i>{" "}
</p>
);
})}
</div>
)}
</div>
);
}
export default (ShowAllBeneficiariesPage);

I can't completely fix your issue, because I'd need more context and time, but I've found some issues on your code.
Never ever ever, have something in your render code that has a reference to a useRef variable. When a useRef value changes, react will completely ignore it and will not update your component. Use setState for those.
It sounds like your allBeneficiaries instead of being a ref or a state it's just derived state: It looks like it's a derived value from beneficiaries. In this case, you don't need to use any hook, just declare it as a const (e.g. const allBeneficiaries = getBeneficiaries(beneficiaries)). If you have performance issues, then consider using useMemo, but it should not be needed.
Never use a useRef as a dependency value in a useEffect - Same thing, react doesn't care about ref values, so you'll have unexpected behaviour there (effects retriggering when it shouldn't, effects not triggering when they should)
Try to avoid useEffect as much as posible. It should only be used for specific cases, such as fetching something from a server or manipulating the dom. For the rest of them, it's just problematic, best avoided.

Using allBeneficiaries (or any other ref object) as a dependency for a hook won't help you at all. The ref object's identity will never change over the lifetime of a component.
If you want to run an effect/... when the value boxed within the allBeneficiaries ref changes, the dependency will need to be allBeneficiaries.current.
Beside that, there's no good reason to use a ref for allBeneficiaries. Since it affects rendering, you will want to save it as a state atom (useState).

Problem updating parent state from child component in React

I have a class component(actually the collection of the same components) where I have 2 buttons + and - to increase and decrease quantity of watches. Min amount of watches is 1 and max amount is 10. I have regulated this with this 2 functions increaseAmountHandler and decreaseAmountHandler. With this two buttons it's all ok. But the problem is that I have to sum up the value of calculated watches in parent component and I cannot forward the summed up values of the watches to a parent component to state variable totalAmount. Cannot use Redux becacuse it's a collection of watches component and each have own + and - button already occupied with this 2 increaseAmountHandler, decreaseAmountHandler functions.
Anyone idea how to solve this?
Child component:
import React, { Component } from 'react';
import Modal from '.././UI/Modal';
class SelectedWatch extends Component {
constructor(props) {
super(props)
this.state = {
watchQuantity: 1,
watchAmount: 1
}
}
increaseAmountHandler = () => {
if(this.state.watchQuantity < 1) {
this.setState({
watchQuantity: 0,
watchAmount: 0
})
return;
} else if (this.state.watchQuantity >= 10){
this.setState({
watchQuantity: 10,
watchAmount: this.props.selectedWatch.selectedWatchPrice * this.state.watchQuantity
})
return;
}
this.setState({
watchQuantity: this.state.watchQuantity + 1,
watchAmount: this.props.selectedWatch.selectedWatchPrice * this.state.watchQuantity
})
}
decreaseAmountHandler = () => {
if(this.state.watchQuantity < 1) {
this.setState({
watchQuantity: 0,
watchAmount: 0
})
return;
} else if (this.state.watchQuantity >= 10){
this.setState({
watchQuantity: 9,
watchAmount: this.props.selectedWatch.selectedWatchPrice * this.state.watchQuantity
})
return;
}
this.setState({
watchQuantity: this.state.watchQuantity - 1,
watchAmount: this.props.selectedWatch.selectedWatchPrice * this.state.watchQuantity
})
}
render() {
return (
<div className={"shopping-cart-product" + (this.state.watchQuantity < 1 ? ' notDisplayed' : '')}>
<div className="product-info">
<div>
<h3>{this.props.selectedWatch.selectedWatchName}</h3>
<p>${this.props.selectedWatch.selectedWatchPrice} × {this.state.watchQuantity}</p>
</div>
<img src={this.props.selectedWatch.selectedWatchUrl} />
</div>
<div className="product-count">
<button onClick={this.decreaseAmountHandler}>-</button>
<span>{this.state.watchQuantity}</span>
<button onClick={this.increaseAmountHandler}>+</button>
</div>
</div>
);
}
}
export default SelectedWatch;
Parent component:
import React, { Component } from 'react';
import EnteredWatch from '.././components/EnteredWatch/EnteredWatch';
import SelectedWatch from '.././components/SelectedWatch/SelectedWatch';
class App extends Component {
constructor(props) {
super(props)
this.state = {
watchName: '',
watchDescription: '',
watchUrl: '',
watchPrice: '',
watchId: '',
watchAmount: '',
watchQuantity: 1,
enteredWatchList: [],
selectedWatchName: '',
selectedWatchDescription: '',
selectedWatchUrl: '',
selectedWatchPrice: '',
selectedWatchId: '',
selectedWatchAmount: '',
selectedWatchQuantity: 1,
selectedWatchList: [],
totalAmount: 0,
}
}
submitHandler = (event) => {
event.preventDefault();
let watchId = Math.floor((Math.random() * 100) + 1);
let watchName = this.state.watchName;
let watchDescription = this.state.watchDescription;
let watchUrl = this.state.watchUrl;
let watchPrice = this.state.watchPrice;
let watchQuantity = this.state.watchQuantity;
this.setState({
enteredWatchList: this.state.enteredWatchList.concat({watchName, watchUrl, watchDescription, watchPrice, watchId, watchQuantity})
})
add = (selectedWatchName, selectedWatchUrl, selectedWatchDescription, selectedWatchPrice, index, selectedWatchQuantity) => {
let arr = this.state.selectedWatchList;
let found = arr.some(el => {
return el.selectedWatchName === selectedWatchName;
});
if (!found) {
return arr.concat({selectedWatchName, selectedWatchUrl, selectedWatchDescription, selectedWatchPrice, index, selectedWatchQuantity});
} else {
return this.state.selectedWatchList;
}
}
buyWatchHandler = (selectedWatchName, selectedWatchUrl, selectedWatchDescription, selectedWatchPrice, index, selectedWatchQuantity) => {
let arr = this.add(selectedWatchName, selectedWatchUrl, selectedWatchDescription, selectedWatchPrice, index, selectedWatchQuantity);
this.setState({
selectedWatchName: selectedWatchName,
selectedWatchUrl: selectedWatchUrl,
selectedWatchDescription: selectedWatchDescription,
selectedWatchPrice: selectedWatchPrice,
selectedWatchId: index,
selectedWatchQuantity: selectedWatchQuantity,
selectedWatchList: arr
});
}
render() {
const enteredWatches = this.state.enteredWatchList.map((enteredWatch, index) => {
return <EnteredWatch
key={index}
enteredWatch={enteredWatch}
selected={this.buyWatchHandler.bind(this, enteredWatch.watchName, enteredWatch.watchUrl,
enteredWatch.watchDescription, enteredWatch.watchPrice, index, enteredWatch.watchQuantity)}
/>
});
const selectedWatches = this.state.selectedWatchList.map((selectedWatch, index) => {
const active = this.state.activeIndex;
return <SelectedWatch
key={index}
active={index === active}
selectedWatch={selectedWatch}
/>
});
return (
<div className="App">
<div className="container-fluid">
<div className="container">
<div className="add-product">
<form>
<div>
<label>Product name:</label>
<input
type="text"
placeholder="Casio Watch"
required
value={this.state.watchName}
onChange={event => this.setState({watchName: event.target.value})}
/>
</div>
<div>
<label>Product description:</label>
<textarea
placeholder="Sample description..."
value={this.state.watchDescription}
onChange={event => this.setState({watchDescription: event.target.value})}
>
</textarea>
</div>
<div>
<label>Product image:</label>
<input
type="text"
placeholder="http://...jpg"
value={this.state.watchUrl}
pattern="https?://.+" required
onChange={event => this.setState({watchUrl: event.target.value})}
/>
</div>
<div>
<label>Product price:</label>
<input
type="number"
min="0"
placeholder="22"
value={this.state.watchPrice}
onChange={event => this.setState({watchPrice: event.target.value})}
/>
</div>
<button
type="submit"
onClick={event => this.submitHandler(event)}
>
Add a new Task
</button>
</form>
</div>
<div className="list-products">
<ul>
{enteredWatches}
</ul>
</div>
<div className="shopping-cart">
<div className="shopping-cart-products">
<ul>
{selectedWatches}
</ul>
</div>
<div className="shopping-cart-summary">
<div>Total: <b>${this.state.totalAmount}</b></div>
<div><button onClick={this.summaryHandler}>Purchase</button></div>
</div>
</div>
</div>
</div>
</div>
);
}
}
export default App;

The parent has to keep track of how many watches have been added.
Make the parent smart (has state), and the children dumb (no state).
Manage all the state in the parent, and put the click handlers in the parent too.
Pass those handlers down to the child, to be fired when its buttons are clicked. Something like this:
class Parent extends React.Component {
this.state = {
cart: [],
watches: [
{ id: 1, name: "Casio", description: "...", price: 25 },
{ id: 2, name: "Rolex", description: "...", price: 3000 },
{ id: 3, name: "Timex", description: "...", price: 10 },
],
}
handleClickIncrement = (watchId) => {
//add it to the cart (or increment it if its already there)
}
handleClickDecrement = (watchId) => {
//remove it from the cart (or deccrement it if its already there)
}
getCartTotal() {
//loop over cart and calculate
}
renderWatches() {
this.state.watches.map(watch => (
<Watch id={watch.id}
name={watch.name}
description={watch.description}
price={watch.price}
onClickIncrement={() => { this.handleClickIncrement(watch.id); }}
onClickDecrement={() => { this.handleClickDecrement(watch.id); }}
))
}
render() {
<div>
<h1>Our selection of watches:</h1>
{this.renderWatches()}
<h1>Your cart total: {this.getCartTotal()}</h1>
</div>
}
}
class Watch extends React.Component {
props = {
id,
name,
description,
price,
quantityInCart,
onClickIncrementButton,
onClickDecrementButton
}
render() {
<div>
<h1>{this.props.name}</h1>
<p>{this.props.description}</p>
<h5>${this.props.price}</h5>
<button onClick={this.props.onClickIncrementButton}>+</button>
<button onClick={this.props.onClickDecrementButton}>-</button>
</div>
}
}

React - set state on unmounted component

I tried a lot of ways to make it works but it didn't. Probably I don't understand the React idea or I missed something. My child via callback try to modify the global/parent state and then I got the well known error.
index.js:1452 Warning: Can't call setState (or forceUpdate) 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.
I try to use variable _isMounted so before setState I did:
if (this.isMounted()) {
this.setState({...});
}
Unfortunately it doesn't work.
The problem is when the function this.handleChangeAlgorithms is invoked from the child.
My code
class ConfigurationForm extends Component {
constructor(props) {
super(props);
this.state = {
choosenAlgorithm: null,
htmlType: null,
customHtml: null,
isOpenModal: false,
generatedHTMlConfig: {
headers: 1,
paragraphs: 1,
buttons: 1,
links: 1,
inputs: 1,
images: 1,
},
};
}
handleChangeAlgorithms = event => {
let algorithmName = event.target.value;
let newChoosenAlgorithm = this.props.algorithms.filter(
e => e.value === algorithmName,
)[0];
// this.setState({choosenAlgorithm: newChoosenAlgorithm});
this.props.callbackConfigurationForm(algorithmName);
};
handleChangeHtmlType(event) {
let newHtmlType = event.target.value;
console.log(newHtmlType);
if (newHtmlType === "default") {
this.setState({ isOpenModal: true });
} else {
this.setState({ htmlType: newHtmlType });
}
}
handleUserFile(event) {
let file = event.target.files[0];
this.setState({ customHtml: file });
this.props.callbackConfigurationFormPreview(file);
}
handleSubmit(event) {
event.preventDefault();
let htmlContent = null;
let htmltypeKey = Object.keys(HtmlType).find(
key => HtmlType[key] === HtmlType.default,
);
console.log(htmltypeKey);
// if (this.state.htmlType === 'default'){
// htmlContent = this.loadTemplate();
htmlContent = generateHTML(this.state.generatedHTMlConfig);
console.log(htmlContent);
// } else {
// htmlContent=this.state.customHtml;
// }
let config = {
algorithm: this.state.choosenAlgorithm,
html: htmlContent,
};
console.log(config);
this.props.callbackConfigurationForm(config);
}
loadTemplate() {
let loadedTemplate = null;
let file = "html-templates/example.html";
let request = new XMLHttpRequest();
request.open("GET", file, false);
request.send(null);
if (request.status === 200) {
loadedTemplate = request.responseText;
}
return loadedTemplate;
}
renderHtmlTypesList = () => {
let list = [];
for (const htmlKey of Object.keys(HtmlType)) {
list.push(
<option key={htmlKey} value={htmlKey}>
{HtmlType[htmlKey]}
</option>,
);
}
return list;
};
generateHTMLFromPopup() {
this.setState({ isOpenModal: false });
}
changeHeaders(event, type) {
console.log(type);
console.log(event.target.value);
let prevConfig = { ...this.state.generatedHTMlConfig };
switch (type) {
case "Headers":
prevConfig.headers = event.target.value;
this.setState({ generatedHTMlConfig: prevConfig });
break;
case "Paragraphs":
prevConfig.paragraphs = event.target.value;
this.setState({ generatedHTMlConfig: prevConfig });
break;
case "Buttons":
prevConfig.buttons = event.target.value;
this.setState({ generatedHTMlConfig: prevConfig });
break;
case "Links":
prevConfig.links = event.target.value;
this.setState({ generatedHTMlConfig: prevConfig });
break;
case "Inputs":
prevConfig.inputs = event.target.value;
this.setState({ generatedHTMlConfig: prevConfig });
break;
case "Images":
prevConfig.images = event.target.value;
this.setState({ generatedHTMlConfig: prevConfig });
break;
}
}
render() {
return (
<Row>
{/* todo 12.11.2018 extract to another component! */}
<Modal
open={this.state.isOpenModal}
header="Generate Html"
actions={
<div>
<Button
modal="close"
waves="light"
className="red lighten-2"
>
Cancel
</Button>
<Button
modal="close"
waves="light"
className="blue"
onClick={this.generateHTMLFromPopup.bind(this)}
>
<Icon left>build</Icon>Generate
</Button>
</div>
}
>
<p>Choose HTML elements for generated HTML.</p>
<Input
type="number"
label="Headers"
value={this.state.generatedHTMlConfig.headers}
onChange={e => this.changeHeaders(e, "Headers")}
/>
<Input
type="number"
label="Paragraphs"
value={this.state.generatedHTMlConfig.paragraphs}
onChange={e => this.changeHeaders(e, "Paragraphs")}
/>
<Input
type="number"
label="Buttons"
value={this.state.generatedHTMlConfig.buttons}
onChange={e => this.changeHeaders(e, "Buttons")}
/>
<Input
type="number"
label="Links"
value={this.state.generatedHTMlConfig.links}
onChange={e => this.changeHeaders(e, "Links")}
/>
<Input
type="number"
label="Inputs"
value={this.state.generatedHTMlConfig.inputs}
onChange={e => this.changeHeaders(e, "Inputs")}
/>
<Input
type="number"
label="Images"
value={this.state.generatedHTMlConfig.images}
onChange={e => this.changeHeaders(e, "Images")}
/>
</Modal>
<h2>Algorithm</h2>
<Row>
<Input
s={12}
type="select"
label="Select algorithm"
defaultValue=""
onChange={this.handleChangeAlgorithms}
>
<option value="" disabled>
Choose an algorithm
</option>
{this.props.algorithms.map(item => (
<option key={item.value} value={item.value}>
{item.name}
</option>
))}
</Input>
</Row>
{this.state.choosenAlgorithm ? (
<Collapsible popout>
<CollapsibleItem header="Details" icon="notes">
<ol>
{this.state.choosenAlgorithm.details.steps.map(
(step, index) => (
<li key={index}>{step}</li>
),
)}
</ol>
</CollapsibleItem>
</Collapsible>
) : null}
<h2>HTML to obfuscate</h2>
<Row>
<Input
s={12}
type="select"
label="HTML type"
defaultValue=""
onChange={this.handleChangeHtmlType}
>
<option value="" disabled>
Choose HTML
</option>
{this.renderHtmlTypesList()}
</Input>
</Row>
{this.state.htmlType === "custom" ? (
<Row>
<Input
type="file"
label="File"
onChange={this.handleUserFile}
/>
</Row>
) : null}
<div className="center-align">
<Button type={"button"} onClick={this.handleSubmit}>
Process<Icon left>autorenew</Icon>
</Button>
</div>
</Row>
);
}
}
class App extends Component {
_isMounted = false;
constructor(props) {
super(props);
this.state = {
isMounted: false,
//export to enum
algorithms: [
{
name: "Html to Javascript",
value: "1",
details: {
steps: [
"Split HTML file line by line.",
"Replace white characters.",
"Create function which add lines to document using document.write function.",
],
},
},
{
name: "Html to Unicode characters",
value: "2",
details: {
steps: [
"Create js function encoding characters to Unicode characters.",
"Create decoding function.",
"Add output from decoding function to HTML.",
],
},
},
{
name: "Html to escape characters",
value: "3",
details: {
steps: [
"Change endcoding using escape javascript function.",
"Decode using unescape javascript function.",
"Add element to HTML.",
],
},
},
{
name:
"Using own encoding and decoding function. [NOT IMPLEMENTED YET]",
value: "4",
details: {
steps: [
"Encode HTML using own function.",
"Save encoded content into js variable.",
"Decode using own decoding function.",
"Add element to HTML document.",
],
},
},
{
name: "Combine above methods [NOT IMPLEMENTED YET]",
value: "5",
details: {
steps: ["To be done..."],
},
},
],
previewHtml: null,
obfuscationConfig: null,
activeTab: 1,
};
}
componentDidMount() {
this._isMounted = true;
}
componentWillUnmount() {
this._isMounted = false;
}
processDataFromConfigurationForm = config => {
console.info(config);
if (this._isMounted) {
this.setState({
test: Date.now(),
// obfuscationConfig: config,
// doObfuscation: true,
// activeTab:3,
// previewHtml: config.html
});
}
};
render() {
return (
<div>
<header className="App">
<h1>HTML obfuscator</h1>
</header>
<Tabs>
<Tab
title="Configuration"
active={this.state.activeTab === 1}
>
<ConfigurationForm
algorithms={this.state.algorithms}
config={this.state.obfuscationConfig}
callbackConfigurationForm={
this.processDataFromConfigurationForm
}
/>
</Tab>
<Tab
title="HTML Preview"
active={this.state.activeTab === 2}
disabled={!this.state.previewHtml}
>
<HTMLPreview previewHtml={this.state.previewHtml} />
</Tab>
<Tab
title="Result"
active={this.state.activeTab === 3}
disabled={!this.state.obfuscationConfig}
>
{this.state.obfuscationConfig ? (
<ObfuscationOutput
config={this.state.obfuscationConfig}
/>
) : null}
</Tab>
</Tabs>
</div>
);
}
}
export default App;
The error

Try to add a constructor to your parent class, indeed, you can initialize the component state before the first modification:
class App extends Component {
constructor(props) {
super(props);
this.state = {
test1: Date.now()
};
}
// here you can update the state as you want, for example
foobar(event) {
this.setState({test1: event.target.value });
}
}
Hope it can help you...

Setting the state inside of the lifecycle method componentDidMount() should do the trick.
Oh I didn't see that someone already suggested that, glad you got it working

not able to display material-ui dropdown with props values

I am trying to incorporate material-ui DropDown element into my page but I am getting map errors
My page code
import React, {Component} from 'react';
import {Button, Dropdown, Form} from 'semantic-ui-react'
import SimpleReactValidator from 'simple-react-validator';
import cookie from 'react-cookies'
import {Redirect} from 'react-router-dom'
const jsonData = require('../../../../../jsonData/data.json');
const dummyData = require('../../../../../jsonData/dummy.json');
import auth, {
axiosInst as axios,
removeElement,
addElement,
beforeSubmiteShaker,
afterSubmiteShaker
} from "../../../../helper";
import QuestionsFilters from '../../../../components/QuestionsFilters'
import DropDown from '../../../../components/ui/Select/Select'
const items = [
{value: 1, primaryText: 'Dhaval'},
{value: 2, primaryText: 'Dhavalu'},
{value: 3, primaryText: 'Dhavalaa'},
]
class RegisterCandidate extends Component {
constructor(props) {
super(props);
this.state = {
firstname: "",
lastname: "",
mobile_no: "",
email: "",
password: "",
city_id: "",
preference_list: [],
medium: "", //how did u find us
is_looking_for: "",
affiliate: "",
revert: "",
emailExist: "",
mobileExist: "",
isLogin: false,
historyRoute: "",
};
this.validator = new SimpleReactValidator();
}
componentDidMount() {
this.props.fetchCities()
this.props.fetchPreferences()
}
change(e) {
this.setState({
[e.target.name]: e.target.value
})
};
dropDownChange(e, {value, name}) {
this.setState({
[name]: value
})
}
emailcheck(e) {
if (this.validator.fieldValid('email')) {
let uri = '/email/exists';
axios.get(uri, {
params: {email: this.state.email}
})
.then((response) => {
this.setState({emailExist: response.data});
if (response.data.status != 'Failed') {
removeElement("p[id='serv-error email-exist']")
return axios.get('/droppedregistrations/add', {
params: {email: this.state.email}
}).then((response) => {
console.log("Email Dropped " + response.data)
}).catch((error) => {
console.log('failed')
})
} else {
removeElement("p[id='serv-error email-exist']")
addElement("#email", "serv-error email-exist", "This email already exists.")
}
})
.catch(error => {
console.log('error Email')
})
}
}
mobilecheck(e) {
if (this.state.mobile_no != isNaN && this.state.mobile_no.length == 10) {
let uri = '/number/exists';
axios.get(uri, {
params: {mobile_no: this.state.mobile_no}
}).then((response) => {
this.setState({mobile_noExist: response.data});
if (response.data.status != 'Failed') {
removeElement("p[id='serv-error mobile-exist']")
return axios.get('/droppedregistrations/add', {
params: {mobile_no: this.state.mobile_no}
}).then((response) => {
console.log("mobile dropped " + response.data)
}).catch((error) => {
console.log('failed')
})
} else {
removeElement("p[id='serv-error mobile-exist']")
addElement("#mobile_no", "serv-error mobile-exist", "This mobile already exists.")
}
})
.catch(error => {
console.log('You are experiencing slow internet please be patient and try again later')
})
}
}
addUserSubmit(e) {
e.preventDefault();
beforeSubmiteShaker("s_reg_submit", "shaker")
if (this.validator.allValid()) {
const userDetails = {//add data to a donstant to pot
firstname: this.state.firstname,
lastname: this.state.lastname,
email: this.state.email,
password: this.state.password,
mobile_no: this.state.mobile_no,
city_id: this.state.city_id,
medium: this.state.medium,
is_looking_for: this.state.is_looking_for,
preference_list: this.state.preference_list,
affiliate: this.state.affiliate
}
let uri = '/register/candidate';
axios.post(uri, userDetails)
.then((response) => {
this.setState({revert: response.data});
const gotBack = this.state.revert
if (gotBack.status === 'Success') {
cookie.remove('token')
cookie.save('token', gotBack.token, {path: '/'})
if (cookie.load('token')) {
this.setState({isLogin: true})
}
else {
console.log('Something went wrong while redirect.')
}
}
})
.catch(error => {
if (error.response.status === 422) {
afterSubmiteShaker("s_reg_submit", "shaker")
$.each(error.response.data.errors, function (index, value) {
var errorDiv = '#' + index;
$(errorDiv).after("<p id='serv-error' class='validation-message'>" + value + "</p>");
});
}
})
} else {
this.validator.showMessages();
this.forceUpdate();
afterSubmiteShaker("s_reg_submit", "shaker")
}
}
render() {
const {
firstname,
lastname,
mobile_no,
email,
password,
city_id,
preference_list,
medium,
is_looking_for,
affiliate,
isLogin
} = this.state;
//to get the items in level of education
let looking_for = jsonData.looking_for;
var looking_fors = []
for (let i = 0; i < looking_for.length; i++) {
looking_fors.push(looking_for[i]['value']);
}
if (isLogin) {
return <Redirect to='/register/candidate/step2'/>;
} else {
return (
<section className="container mt-3">
{/*one click register section*/}
<div className="row p-3">
<div className="col-md-6">
<div className="card text-center">
<div className="card-body">
<h3>Register Using</h3>
<br/>
<a href="/" className={"btn btn-block btn-lg btn-info"}> Register with Facebook</a>
<a href="/google/redirect" className={"btn btn-block btn-lg btn-danger"}> Register
with Google</a>
<br/>
</div>
</div>
</div>
{/*end of one click register section*/}
{/*manuel register section*/}
<div className="col-md-6">
<div id="shaker" className="card">
<div className="card-body">
<h5 className="card-title">Register Candidate</h5>
<Form onSubmit={this.addUserSubmit.bind(this)}>
<Form.Field>
<label>First Name*</label>
<input name="firstname" id="firstname" value={firstname}
onChange={e => this.change(e)} type="text"
placeholder='Enter First Name*'/>
{this.validator.message('first name', firstname, 'required|alpha')}
</Form.Field>
<Form.Field>
<label>Last Name*</label>
<input name="lastname" id="lastname" value={lastname}
onChange={e => this.change(e)} type="text"
placeholder='Enter Last Name'/>
{this.validator.message('last name', lastname, 'required|alpha')}
</Form.Field>
<Form.Field>
<label>Mobile No*</label>
<input name="mobile_no" id="mobile_no" value={mobile_no}
onBlur={this.mobilecheck.bind(this)} onChange={e => this.change(e)}
type="text" placeholder='Enter mobile_no'/>
{this.validator.message('mobile no.', mobile_no, 'required|phone|min:10|max:10')}
</Form.Field>
<Form.Field>
<label>Email*</label>
<input name="email" id="email" value={email}
onBlur={this.emailcheck.bind(this)} onChange={e => this.change(e)}
type="text" placeholder='Enter Email'/>
{this.validator.message('email', email, 'required|email')}
</Form.Field>
<Form.Field>
<label>Password*</label>
<input name="password" id="password" value={password}
onChange={e => this.change(e)} type="password"
placeholder='Enter Password'/>
{this.validator.message('password', password, 'required|min:6')}
</Form.Field>
<Form.Field>
<label>City*</label>
<Dropdown placeholder='Select City' id="city_id" name="city_id" search
selection options={this.props.city_opt} value={city_id}
onChange={this.dropDownChange.bind(this)}/>
{this.validator.message('city', city_id, 'required|gt:0')}
</Form.Field>
<Form.Field>
<label>Preference*</label>
<Dropdown placeholder='Select Preference' id="preference_list"
name="preference_list" search multiple selection
options={this.props.preference_list_opt} value={preference_list}
onChange={this.dropDownChange.bind(this)}/>
{this.validator.message('preference', preference_list, 'required|max:3', false, {max: 'Maximum 3 preferences allowed'})}
</Form.Field>
<Form.Field>
<label>How did you find us?*</label>
<Dropdown placeholder='Please Select' id="medium" name="medium" search
selection options={jsonData.medium} value={medium}
onChange={this.dropDownChange.bind(this)}/>
{this.validator.message('medium', medium, 'required')}
</Form.Field>
<Form.Field>
<label>What are you looking for?*</label>
<Dropdown placeholder='Please Select' id="is_looking_for"
name="is_looking_for" search selection
options={jsonData.looking_for} value={is_looking_for}
onChange={this.dropDownChange.bind(this)}/>
{this.validator.message('', is_looking_for, 'required|in:' + looking_fors)}
</Form.Field>
<Form.Field>
<label>affiliate Code</label>
<input name="affiliate" value={affiliate} onChange={e => this.change(e)}
type="text" placeholder='Enter preference_list'/>
</Form.Field>
<Button id="s_reg_submit" className={"btn btn-block btn-lg"}
type='submit'>Submit</Button>
</Form>
<QuestionsFilters/>
</div>
</div>
</div>
{/*end of manuel register section*/}
<DropDown items={items}/>
</div>
</section>
)
}
}
}
export default RegisterCandidate;
my DropDown component code
import React, {Component} from 'react';
import DropDownMenu from 'material-ui/DropDownMenu';
import MenuItem from 'material-ui/MenuItem';
const styles = {
customWidth: {
width: 200,
},
};
class DropDownMenuSimpleExample extends Component {
constructor(props) {
super(props);
this.state = {value: 1, items: ['abcd', 'efgh']};
}
handleChange(event, index, value) {
return this.setState({value})
}
render() {
let propItems = this.props.items
return (
<DropDownMenu
value={this.state.value}
onChange={this.handleChange.bind(this)}
style={styles.customWidth}
autoWidth={false}
>
{(propItems !== null || propItems != 'undefined' ) ? (propItems).map((item, index) => <MenuItem key={index} value={1}
primaryText="Custom height"/>) : (this.state.items).map((item, index) =>
<MenuItem key={index} value={1} primaryText="Custom width"/>)}
</DropDownMenu>
);
}
}
export default DropDownMenuSimpleExample
it is telling me that It cannot call map on null and in the first render the value of props shows undefined but then it is defined so not able to get to render the DropDown element properly..
any help will be highly appreciated
Please Note :- with just the state I get the proper dropdown but the issue happens only when I am passing props as data for the dropdown