Capture this.name of a button in React onClick [duplicate] - javascript

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ReactJS, event.currentTarget doesn't have the same behavior as Vanilla Javascript
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I want to capture the name attribute of a button on click in React.
I tried the following code block:
export function TestButton(props){
function logName() {
console.log(this.name)
}
return(
<button name={props.name} onClick={event => logName(event.currentTarget.getAttribute("name"))} type='button'>{props.text}</button>
)
}
My expectation was that this code would allow me to create a button that displays the name in the console log:
<TestButton name='helloWorld' text='Click Me'/>
Instead I get an alert that this is undefined. This is in spite of my ability to see the name when I inspect the element.
I have also tried target instead of currentTarget with no luck. I also tried event.currentTarget.name without the results I desire.
What did i miss?

In react, I believe this is reserved for classes, whereas you are defining a functional component. In a functional component, the comparable state value would be stored with useState(). That being said, I'm not sure I see the need for that here, since this button is getting its props from somewhere and the value of name and text are not changing in this component. I would code it this way:
export const TestButton = ({props}) => {
return(
<button name={props.name} onClick={() => console.log(props.name)}>
{props.text}
</button>
)
}
Now to go a bit further, maybe you want to use state wherever this button is being rendered. That could look like this:
import {TestButton} from "./someFile";
const [name, setName] = useState("some-button");
const [text, setText] = useState("click me!");
// now there could be some code here that decides what the name or text would be
// and updates the values of each with setName("name") and setText("text")
const Page = () => (
<>
<TestButton props={{name: name, text: text}} />
</>
)
This is all building off your current code, but now I will combine everything in a way that makes sense to me:
import {useState} from "react";
const [name, setName] = useState("some-button");
const [text, setText] = useState("click me!");
// some code to determine/change the value of the state vars if necessary
const TestButton = ({name, text}) => {
return(
<button name={name} onClick={() => console.log(name)}>
{text}
</button>
)
}
export const Page = () => (
<>
<TestButton name={name} text={text} />
</>
)

Pleas try as follows:
export function TestButton(props){
function logName() {
console.log(props.name)
}
return(
<button name={props.name} onClick={() => logName()} type='button'>{props.text}</button>
)
}

Try this
export function TestButton(props){
const logName = (e, name) => {
console.log("name attribute ->", name)
}
return(
<button name={props.name} onClick={ (e) => logName(e, props.name)} type='button'>{props.text}</button>
)
}

Related

Way to render a new component onClick in react js

Am trying to render a new component onclick a button in react js. Am using functional components and I can't handle it. Eg: am in the UserManagement component and on a button click I need to render another component named employee management.
You can conditionally render your component.
Example :
EmployeeManagement.js
const EmployeeManagement = () => {
....
return (
<div>
EmployeeManagement
</div>
);
}
UserManagement.js
const UserManagement = () => {
const [hasRender, setRender] = useState(false);
const onShow = React.useCallback(() => setRender(true), []);
return (
<>
<button onClick={onShow}>Show Employee Management</button>
{hasRender && <EmployeeManagement />}
</>
)
}
One way to do this would be to add a local state in UserManagement,
that holds a boolean value indication whether the component should be hidden or shown.
Then you will have something like:
function UserManagement() {
const [compIsShown, setCompIsShown] = useState(false);
return (
// Whatever else you're rendering.
<button onClick={() => setCompIsShown(true)}>...</button>
{compIsShown && <OtherComp />}
)
}
What will happen is that compIsShown will initialize as false,
so this condition compIsShown && <OtherComp /> will prevent it from rendering.
Then, when you click the button, the state will set, causing a re-render, except now the condition will be true, so <OtherComp> will be rendered.
There are other ways to go about this.
Depends mostly on the use-case.
use a visible state & toggle it in onClick:
const [visible, setVisible] = useState(false)
onClick = () => {setVisible(true)}
then render it like this:
{visible && <EmployeeManagement onClick={onClick} />}

Is there a way to make a button function, that when pressed changes the title of another component in React?

I'm trying to make a music app, where on the frontpage there's buttons. When you press one of the buttons, a card pops up. I want the cards title to be depended by which button have been pressed. I'm using react for my project. Is there any way this is possible?
I have this function for my buttons
export function GenreButton({ text }) {
return <StyledGenreButton>{text}</StyledGenreButton>
export function Button (){
return (
<>
<Wrapper>
<GenreButton text='Country' />
<GenreButton text='Disco' />
<GenreButton text='Funk' />
<GenreButton text='House' />
</Wrapper>
</>
)
}
And for my card component:
const CardTitle2 = () => {
const [cardTitle, setCardTitle] = useState ('string')
return <StyledCardTitle onClick={() => setCardTitle('New Title')}>{cardTitle}</StyledCardTitle>
So far, i've tried importing the Card component into my Button component, added an onClick property to my GenreButton function.
export function GenreButton({ text, onClick }) {
return <StyledGenreButton>{[text, onClick]}</StyledGenreButton>
And then inserting an onClick onto one of the GenreButtons in the return statement.
Now i know, that my card title will be changed from 'string' to 'New Title', when i press the title. But is it possible that i can change the title of my card to be equal to my string input from the button?
So i figured out how to do it.
export function Button (){
const [title, setTitle] = useState('')
function GenreButton({ text }) {
return <StyledGenreButton onClick={() => setTitle(text)}>{text}</StyledGenreButton>
}
<Wrapper>
<GenreButton text='Country'/>
<GenreButton text='Disco' />
<GenreButton text='Electro' />
</Wrapper>
<CardWrapper>
<CardTitle title={title} />
</CardWrapper>
You should lift state up, e.g lift state up to your home page:
const HomePage = () => {
const [title, setTitle] = useState('string')
return (
<Card title={title}/>
<Buttons setTitle={setTitle}/>
)
}
For reference: https://reactjs.org/docs/components-and-props.html

why does my prop cease to exist after initially existing when I pass it through to a functional component?

This is the function where I am passing the onClick prop (setShowModal is setState() from the useState hook):
<MyFunctionalComponent
onClick={() => setShowModal(true)}
...other props here
/>
This is the functional component that receives the prop:
export const MyFunctionalComponent = ({ onClick }) => {
return (
<section>
...other code here
{onClick && (<Button>{ctaText}</Button>)}
</section>
);
};
But the Button component never appears, because the prop onClick is undefined. When I console.log the prop inside the functional component, it initially prints the function in the console, but then prints two more times as undefined. Could someone explain why that would be? I got it to work by spreading ...props instead. But the console.log remains the same? I don't understand why. This is my first question on Stack Overflow, so feel free to give me feedback on how to ask better questions :)
The reason why you are receiving an 'undefined' response is because as #Zrogua mentioned, onClick is an event listener function rather than a persistent value (like state you define).
import React from "react";
const YourButton = ({ onClick }) => {
console.log(onClick);
return <section>{onClick && <button>here</button>}</section>;
};
const ParentDiv = () => {
return (
<div>
<h1>Button Props</h1>
<h2>Start editing to see some magic happen!</h2>
<YourButton onClick={() => console.log("CLICK")} />
</div>
);
};
export default ParentDiv;
Result of console.log():
function onClick() // index.js:27:25
The reason why this is because props are read-only. From the React Docs:
Whether you declare a component as a function or a class, it must never modify its own props ... Such functions are called “pure” because they do not attempt to change their inputs, and always return the same result for the same inputs.
Therefore your button will only show if the onClick function is defined. For example, if you did not give onClick a function or value, the button will not appear:
import React, { useState } from "react";
const YourButton = ({ onClick }) => {
console.log(onClick);
return (
<section>
{onClick && <button>This button is shown if a button is defined.</button>}
</section>
);
};
const ParentDiv = () => {
return (
<div>
<h1>Button Props</h1>
<YourButton onClick={() => console.log("CLICK")} />
<YourButton /> {/* You won't see this button because the function is not defined. */}
</div>
);
};
export default ParentDiv;
The button appears because the prop has a value that is not undefined (your onClick function), and because it is read-only, you cannot access that function in your child component.
Instead, (1) define the modal state in the parent component and (2) pass the state through props to the button like so:
import React, { useState } from "react";
const YourButton = ({ onClick }) => {
console.log(onClick);
return (
<section>
{onClick && <button>This button is shown if a button is defined.</button>}
</section>
);
};
const AltButton = ({ modal }) => {
return (
<section>
{modal && (
<button>This button is shown the modal state is passed.</button>
)}
</section>
);
};
const ParentDiv = () => {
const [modal, setModal] = useState(false);
return (
<div>
<h1>Button Props</h1>
<YourButton onClick={() => console.log("CLICK")} />
<YourButton />{" "}
{/* You won't see this button because the function is not defined. */}
<section>
<button onClick={() => setModal(!modal)}>OPEN MODAL</button>
</section>
{modal && <p>this is dependent on state</p>}
<AltButton modal={modal} />
</div>
);
};
export default ParentDiv;
Working CodeSandbox: https://codesandbox.io/s/stack-66715327-passingfunctions-92pzr
Finally, if I am reading between the lines and understanding correctly that you are looking to hide a button when a modal is open, here is a little modal wrapper trick I use for buttons that open modals: https://codesandbox.io/s/stack-66715327-modalwrapper-wvl54
You can't pass onClick, onClick is just an event listener. You should pass the state
<MyFunctionalComponent onClick={() => setShowModal(!showModal)}
showModal={showModal}
...other props here />
/>
export const MyFunctionalComponent = ({ showModal }) => {
return (
<section>
...other code here
{showModal && (<Button>{ctaText}</Button>)}
</section>
);
};
I believe this should work. Let me know if this is what you were looking for.
I think that rather then passing callback you should pass variable which decide if component should show or not. Check this example.
export const MyFunctionalComponent = ({ isShow, onClick }) => {
return (
<section>
...other code here
{isShow && <div>something</div>}
</section>
);
};
export default function App() {
const [showModal, setShowModal] = useState(false);
return (
<MyFunctionalComponent
isShow={showModal}
onClick={() => setShowModal(true)}
/>
);
}
I also suppose that you can make mistake and have something other on mind .. like this:
<section>
...other code here
<button onClick={ onClick }>something</button>}
</section>

React - TypeError: Cannot read property 'setState' of undefined (Arrow functions)

I am not able to use setState. My code looks something like:
const FormComp = () => {
const [reader, setReader] = React.useState(0);
//rest of the code
};
const Ques1 = () => {
return (
<>
<button onClick={() => {
this.setState({ reader: "1" });
}}>Click</button>
</>
)
};
This is just a short version of the code. I'm facing problem in this. Please someone help me out.
This code is in same file.
UPDATE:
tried setReader but it throws an error saying setReader is not defined
When you use React.useState you don't do this.setState, in this example you would just do:
<button onClick={() => {
setReader("1");
}}>Click</button>
Should use like this:
import React from 'react';
function App() {
const [reader, setReader] = React.useState(0);
const FormComp = () => {
//rest of the code
return <div>Clicked {reader} times</div>
};
const Ques1 = () => {
return (
<button onClick={() => setReader(reader+1)}>Increase</button>
)
};
return (
<div className="App">
<FormComp />
<Ques1 />
</div>
);
}
export default App;
You can set whatever value you want in setReader function.
since you're using the useState hook, you should call setReader instead of this.setState.
When you use react hooks and functional components, you can throw away (by moment) the concepts about this.setState
Instead to use this.setState({ reader: "1" }) for const [reader, setReader] = React.useState(0); useState Hook. You should use setReader(1) or setReader("1") (According to your old "this.setState({reader: "1"})")
Button onClick be like:
<button onClick={() => setReader(1)}>
Click
</button>
There are two issues in your code.
You're using setState while using react hook useState
useState in being used in one component, trying to access it on another component
So, decide where do you need it, or you want to pass it as prop and/or lift state up?
And use:
onClick={() => setReader(1)}

React Hooks: Transition don't work with Node as Prop

I have a Dropdown made with React Hooks. The button should have Arrow, which rotate. My first Version works fine:
const DropdownMenu= (props) => {
const [open, setOpen] = useState(false);
const openDropdown = (): void => setOpen(prevState => !prevState);
return (
<div>
<Button
onClick={openDropdown}
dropdownIsOpen={open}
>
Text </Button>
<DropdownContent isOpen={isOpen} />
</div>
);
};
export default DropdownMenu;
const Button = (props) => {
return (
<Button Click={props.onClick}>
Text
<Arrow rotate={props.dropdownIsOpen} color={designTheme.color.primary} />
</Button>
);
};
export default Button;
But now I have multiple Dropdowns and want to use them with the same component. I gave the toggleNode as prop. Now the Arrow rotate but without the transition:
const DropdownButton = (props) => {
const [isOpen, setOpen] = useState(false);
const onToggle = (): void => setOpen(prevState => !prevState);
return (
<Dropdown
isOpen={props.isOpen}
onToggle={onToggle}
toggleNode={
<Button dropdownIsOpen={isOpen}>
Text
</Button>
}
/>
);
};
export default DropdownButton;
Have someboy an idea?
Thank you!
my guess is, you are exporting different Button
How can you use Button inside Button, possibly by importing Button from somewhere else. And then you are again exporting Button. This will be confuse for transpiler, as which Button to be exported.
You might want to rename your custom Button to something else
const Button = (props) => {
return (
<Button Click={props.onClick}>
Text
<Arrow rotate={props.dropdownIsOpen} color={designTheme.color.primary} />
</Button>
);
};
export default Button;
Given your Button component takes an onClick prop:
const Button = (props) => {
return (
<Button Click={props.onClick}>
Text
<Arrow rotate={props.dropdownIsOpen} color={designTheme.color.primary} />
</Button>
);
};
NOTE: As #SagarMore points out, there my also be a naming collision between some imported Button component and your Button component.
You may just need to pass a callback to Click (terrible name, BTW, should be onClick, hopefully it was just a typo):
const DropdownButton = (props) => {
const [isOpen, setOpen] = useState(false);
const onToggle = (): void => setOpen(prevState => !prevState);
return (
<Dropdown
isOpen={props.isOpen}
onToggle={onToggle}
toggleNode={
<Button onClick={onToggle} dropdownIsOpen={isOpen}>
Text
</Button>
}
/>
);
};
Passing onToggle to the inner button's onClick handler should now toggle the isOpen state of the DropDown.
This was my fault.
In my Dropdown component I render two different states conditional. So it renders the start or the end state and don't use the animation. I have to render a animation and don't render new when I click so the animation works.

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