React Hook Forms detect that I change the value of text input when I type something (onChange). But can it also detect the change if I enter data to the input by value={value}?
const validator = register(name);
I need something like
onValueSet={(e) => {
validator.onChange(e);
}}
I mean if I just set data by value={value} I get an error that this input is required. I don't want this error, because data was set by value={value}.
Here is my input:
<StyledInput
name={name}
maxLength={100}
value={value}
onChange={(e) => {
validator.onChange(e);
}}
/>
and my validation schema:
const validationSchema = Yup.object().shape({
first_name: Yup.string()
.required("required"),
});
You have to use reset here and call it when you received your initial form data. I assume you're doing an api call and want to set the result to the form. You can do so with useEffect, watching when you're data has resolved and then reset the form with the actual values. This way you don't have to set the value via the value prop and let RHF manage the state of your inputs. You also don't need to set name prop, as RHF's register call returns this prop as well.
const Component = (props) => {
const { result } = useApiCall();
const { register, reset } = useForm();
useEffect(() => {
reset(result)
}, [result]);
return (
...
<StyledInput
{...register('first_name')}
maxLength={100}
/>
...
)
}
Here is a little CodeSandbox demonstrating your use case:
You can define an onfocus or onkeyup event and call the validation function there instead of onChange event.
<StyledInput
name={name}
maxLength={100}
value={value}
onfocus={(e) => {
validator.onChange(e);
}}
/>
Instead of triggering the validator when input changes, you can instead call your validator through the onBlur event. And I am not sure how you are using react-hook-form .. but the useForm hook has a config mode (onChange | onBlur | onSubmit | onTouched | all = 'onSubmit') on when to trigger the validation:
I'm trying to connect material-ui ToggleButtonGroup with redux form and getting issues with this.
Here is my code:
<Field
name='operator'
component={FormToggleButtonGroup}
>
<ToggleButton value='equals'>Equal</ToggleButton>
<ToggleButton value='not_equals'>Not equal</ToggleButton>
</Field>
.. and my component, passed to Field:
const FormToggleButtonGroup = (props) => {
const {
input,
meta,
children
} = props;
return (
<ToggleButtonGroup
{...input}
touched={meta.touched.toString()}
>
{children}
</ToggleButtonGroup>
);
};
export default FormToggleButtonGroup;
the problem is, when I select value (toggle option), selected value is not passed to redux store, it passed only after loosing focus and then throws error 'newValue.splice is not a function'
Please help to deal with this issue
Sandbox with sample code
Playing with the component I finally found the solution.
I need manually assign new value got from ToggleButtonGroup component and put this value to redux store. Here is how working code looks:
const FormToggleButtonGroup = (props) => {
const {
input,
meta,
children,
...custom
} = props;
const { value, onChange } = input;
return (
<ToggleButtonGroup
{...custom}
value={value}
onChange={(_, newValue) => {
onChange(newValue);
}}
touched={meta.touched.toString()}
>
{children}
</ToggleButtonGroup>
);
};
Main change is getting redux's function onChange and call it with new value, selected when value toggled. There is onChange related to ToggleButtonGroup component and another onChange related to Redux. You need to call latter when ToggleButtonGroup's onChange occurs.
I'm trying to implement a simple checkbox that changes its checked state (true/false) upon clicking. But it does nothing when I click it. For example, upon clicking the checkbox and console logging state.box1 after the click, it's still set to true instead of false. I got the code from Material UI's checkbox example, so I'm confused as to why it doesn't work for me. Any ideas?
state = {
box1: true,
};
handleChange = name => event => {
setState({ name: event.target.checked });
};
<div>
<Checkbox
value="box1"
checked={state.box1}
onChange={this.handleChange('box1')}
label="Primary"
/>
</div>;
Assuming Checkbox component passes the event object to the onChange callback.
Your original handleChange return a callback function but it does not bind to the component context. So your event object will most likely be undefined when you click the checkbox.
you can modify the code to something like this.
// takes both the event object and
handleChange = (event, name) => {
setState([name]: event.target.checked);
};
<Checkbox
value="box1"
checked={state.box1}
onChange={(event) => handleChange(event, 'box1')}
label="Primary"
/>
I've tried to ask this ungooglable to me question dozens of times. I've made almost the simpliest example possible to ask this question now.
I change the value of the hook in the handleChange method. But then console.log always shows previous value, not new one. Why is that?
I need to change the value of the hook and then instead of doing console.log use it to do something else. But I can't because the hook always has not what I just tried to put into it.
const options = ["Option 1", "Option 2"];
export default function ControllableStates() {
const [value, setValue] = React.useState(options[0]);
const handleChange = val => {
setValue(val);
console.log(value);
};
return (
<div>
<div>{value}</div>
<br />
<Autocomplete
value={value}
onChange={(event, newValue) => {
handleChange(newValue);
}}
options={options}
renderInput={params => (
<TextField {...params} label="Controllable" variant="outlined" />
)}
/>
</div>
);
}
You can try it here.
https://codesandbox.io/s/awesome-lumiere-y2dww?file=/src/App.js
I believe the problem is that you are logging the value in the handleChange function. Console logging the value outside of the function logs the correct value. Link: https://codesandbox.io/s/async-fast-6y71b
Hooks do not instantly update the value you want to update, as you might have expected with classes (though that wasn't guaranteed either)
State hook, when calling setValue will trigger a re-render. In that new render, the state will have the new value as you expected. That's why your console.log sees the old value.
Think of it as in each render, the state values are just local variables of that component function call. And think as the result of your render as a result of your state + props in that render call. Whenever any of those two changes (the props from your parent component; the state, from your setXXX function), a new render is triggered.
If you move out the console.log outside of the callback handler (that is, in the body of your rendered), there you will see in the render that happens after your interaction that the state is logged correctly.
In that sense, in your callbacks events from interactions, you just should worry about updating your state properly, and the next render will take care to, given the new props/state, re-render the result
The value doesn't "change" synchronously - it's even declared with a const, so even the concept of it changing inside the same scope doesn't make sense.
When changing state with hooks, the new value is seen when the component is rerendered. So, to log and do stuff with the "new value", examine it in the main body of the function:
const ControllableStates = () => {
const [value, setValue] = React.useState(options[0]);
const handleChange = val => {
setValue(val);
};
// ADD LOG HERE:
console.log('New or updated value:', value);
return (
<div>
<div>{value}</div>
<br />
<Autocomplete
value={value}
onChange={(event, newValue) => {
handleChange(newValue);
}}
options={options}
renderInput={params => (
<TextField {...params} label="Controllable" variant="outlined" />
)}
/>
</div>
);
}
You're printing out the old value in handleChange, not the new val.
i.e.
const handleChange = val => {
setValue(val);
console.log(value);
};
Should be:
const handleChange = val => {
setValue(val);
console.log(val);
};
Actually, lets get a little back and see the logic behind this scenario.
You should use the "handleChange" function ONLY to update the state hook, and let something else do the logic depends on that state hook value, which is mostly accomplished using "useEffect" hook.
You could refactor your code to look like this:
const handleChange = val => {
setValue(val);
};
React.useEffect(() => {
console.log(value);
// do your logic here
}, [value])
So I think that the main problem is that you're not understanding how React
deals with components and states.
So, I'll vastly simplify what React does.
React renders a new component and remembers it's state, it's inputs (aka
props) and it's the state and inputs of the children.
If at any given point an input changes or a state changes, React will render
the component again by calling the component function.
Consider this:
function SomeComponent(text) {
return (<div>The <i>text</i> prop has the value {text}</div>)
}
Let's say the initial prop value is "abc", React will call SomeComponent("abc"), then the function returns
<div>The <i>text</i> prop has the value abc</div> and React will render that.
If the prop text does not change, then React does nothing anymore.
Now the parent component changes the prop to "def", now React will call
SomeComponent("def") and it will return
<div>The <i>text</i> prop has the value def</div>, this is different from
last call, so React will update the DOM to reflect the change.
Now let's introduce state
function SomeComponent() {
const [name, setName] = React.useState("John")
function doSomething()
{
alert("The name is " + name)
}
return (
<p>Current name: {name}</p>
<button onClick={() => setName("Mary")}>Set name to Mary</button>
<button onClick={() => setName("James")}>Set name to James</button>
<button onClick={() => doSomething()}>Show current name</button>
)
}
So here React will call SomeComponent() and render the name John and the 3
button. Note that the value of the name variable does not change during the
current execution, because it's declared as const. This variable only reflects
the latest value of the state.
When you press the first button, setName() is executed. React will internally store
the new value for the state and because of the change of state, it will render
the component again, so SomeComponent() will be called once again. Now the variable name will
reflect again the latest value of the state (that's what useStatedoes), so in this case Mary. React
will realize that the DOM has to be updated and it prints the name Mary.
If you press the third button, it will call doSomething() which will print the
latest value of the name variable because every time React calls
SomeComponent(), the doSomething() function is created again with the latest
value of name. So once you've called setName(), you don't need to do
anything special to get the new value. React will take care of calling the
component function again.
So when you don't use class components but function components, you have to think
differently: the function gets called all the time by React and at any single
execution it reflects the latest state at that particular point in time. So when you
call the setter of a useState hook, you know that the component function will
be called again and useState will return the new value.
I recommend that you read this article, also read again Components and
Props from the React documentation.
So how should you do proceed? Well, like this:
const options = ["Option 1", "Option 2"];
export default function ControllableStates() {
const [value, setValue] = React.useState(options[0]);
const handleChange = val => {
setValue(val);
console.log(value);
};
const handleClick = () => {
// DOING SOMETHING WITH value
alter(`Now I'm going to do send ${value}`);
}
return (
<div>
<div>{value}</div>
<br />
<Autocomplete
value={value}
onChange={(event, newValue) => {
handleChange(newValue);
}}
options={options}
renderInput={params => (
<TextField {...params} label="Controllable" variant="outlined" />
)}
/>
<button type="button" onClick={handleClick}>Send selected option</button>
</div>
);
}
See CodeSandbox.
Here's a react input component:
function Input({ value, setValue }) {
return (
<div>
<input value={value} onChange={event => setValue(event.target.value)} />
<button onClick={() => setValue(value.toUpperCase())}>Capitalize</button>
</div>
);
}
It's just a vanilla input component together with a button that capitalizes the input's value. It's meant to be controlled by some parent component:
function Parent() {
let [value, setValue] = useState("");
return <Input value={value} setValue={setValue} />;
}
This works fine, but it's not idiomatic. To be useable as a "drop-in replacement" for a vanilla input component, it should take an onChange prop, not setValue, the relevant difference being that onChange takes a synthetic event as an argument while setValue takes a string. (I'd like the presence of the capitalize button to be "opaque" to a developer using this Input component.)
I tried to idiomaticize this (see snippet below) by having the input element fire off a change event when the button is clicked, but the this doesn't cause onChange to execute. (I assume that this is due to details of react's synthetic event system that I don't understand. I browsed a bunch of posts on this topic, but couldn't get the ideas I found to work.)
function AnotherInput({ value, onChange }) {
let input = useRef();
let handleClick = () => {
input.current.value = value.toUpperCase();
var event = new Event("change" /* also tried "input" */, {
bubbles: true
});
input.current.dispatchEvent(event); // onChange doesn't fire!
};
return (
<div>
<input value={value} ref={input} onChange={onChange} />
<button onClick={handleClick}>Capitalize</button>
</div>
);
}
Also, I feel I shouldn't have to use a ref here because I don't want to modify the DOM directly; I just want to change the value in the controlling parent component.
Here's a CodePen.
I made it work by simulating the event Object on the Capitalize Button.
Parent Component:
function Parent() {
let [value, setValue] = useState("");
return <Input value={value} onChange={(e) => setValue(e.target.value)} />;
}
Input Component:
EDITED: I've managed to came up with a more elegant solution to the Input Component:
function Input({ value, onChange: inheritedOnChange }) {
return (
<div>
<input value={value} onChange={inheritedOnChange} />
<button value={value.toUpperCase()} onClick={inheritedOnChange}>Capitalize</button>
</div>
);
}
Note that i renamed the onChange prop to inheritedOnChange just for readability purposes. Preserving the onChange name at the destructuring should still work.