Having trouble understanding the syntax in redux-form...
In redux-docs
const renderField = (field) => (
<div className="input-row">
<input {...field.input} type="text"/>
{field.meta.touched && field.meta.error &&
<span className="error">{field.meta.error}</span>}
</div> )
How is the spread operator used inside the input and why does the following returnes an error:
<input {...field.input, id} type="text"/>
The second syntax I dont understand is:
class MyCustomInput extends Component {
render() {
const { input: { value, onChange } } = this.props <---??
return (
<div>
<span>The current value is {value}.</span>
<button type="button" onClick={() => onChange(value + 1)}>Inc</button>
<button type="button" onClick={() => onChange(value - 1)}>Dec</button>
</div>
)
}
}
What is:
input: { value, onChange }
?
Queston 1:
The error from using {...field.input, id} should be something like the following:
Syntax error: ...: Unexpected token, expected }
If you already have props as an object, and you want to pass it in
JSX, you can use ... as a “spread” operator to pass the whole props
object (Spread Attributes)
So it appears the JSX attribute spread is not exactly the same as a es2015 spread. I believe it is limited to just the examples in the react docs.
Question 2:
The Field component passes these props to your wrapped component MyCustomInput
input.onChange(eventOrValue) : Function
A function to call when the form field is changed. It expects to either receive the React SyntheticEvent or the new value of the field.
input.value: any
The value of this form field. It will be a boolean for checkboxes, and a string for all other input types. If there is no value in the Redux state for this field, it will default to ''. This is to ensure that the input is controlled. If you require that the value be of another type (e.g. Date or Number), you must provide initialValues to your form with the desired type of this field.
In other words when MyCustomInput fires onChange the Field component will dispatch an action to update the form store.
The value prop is used to maintain the state MyCustomInput.
Related
How would you read the input value ?
On the reacjs site I see very complicated way !!
https://reactjs.org/docs/forms.html
I just want to read the value and submit it via ajax fetch() request. I.e. I don't need to manage bindings, events and such ...
The easiest way by far to read values from html controls is by using an event handler.
export default class myComponent extends Component {
person = {};
onChange = field => e => {
this.person[field] = e.target.value;
};
render() {
return (
<Input
id="firstName"
name="firstName"
autoComplete="firstName"
autoFocus
onChange={this.onChange('FirstName')}
/>
);
}
}
In the above code snippet we are basically telling react to fire the onChange member on an update of firstName control update. Our method will receive an event e, that has a handle to our control and we can basically probe it's value member to get what's typed in (much like jquery's $('#element').value()).
Why is it the easiest method? because it's generic enough to allow you to handle multiple inputs in a react component. Notice that, I'm also instructing React to pass me the control name in addition to the event, and using this method I can basically know exactly which of my inputs (in case of multiple) caused the event to fire.
Reading user input value is feasible and recommended via event handlers.
Below example would explain how to read input value and send it to the backend via fetch when Form is submitted
class Test extends Component{
constructor(props){
super(props);
this.state = {
name: “”
}
}
handleChange = event => {
this.setState({name: event.target.value});
}
handleSubmit = () => {
//send the value via fetch backend I.e., this.state.name
}
render(){
const { name } = this.state;
render(
<form onSubmit={this.handleSubmit}
<label>
Name:
<input type="text" value={name} onChange={this.handleChange} name="name" />
</label>
<input type="submit" value="Submit" />
</form>
)
}
}
I run into the validation issue using multiple components decorated with same form name.
Let's say we have SimpleForm1 and SimpleForm2. When rendering Only SimpleForm1 with the name field validation works as expected, as well as when rendering SimpleForm2 with the surname field. But when rendering them both on a single page validation for SimpleForm1 is broken.
The question is how to avoid such behaviour and make both validation functions work.
Here is a fiddle which illustrates my problem
It's not a good idea to use same names for multiple forms.
As i understand you need to dynamically add form inputs(SimpleForm2 in your example) and have possibility to submit both forms with one button.
If yes, so you can add just an input to first form, you don't need second form.
Form:
const SimpleFormComponent1 = props => {
const {handleSubmit, pristine, reset, submitting, renderBoth} = props;
const onSubmit = (values) => {
alert(JSON.stringify(values));
};
return (
<form onSubmit={handleSubmit(onSubmit)}>
...
{
renderBoth &&
<Field
name="surname"
type="text"
component={renderField}
label="Surname"
validate={validateSurname}
/>
}
...
</form>
)
};
Render function:
render() {
const {renderBoth} = this.state;
return (
<div>
<div className='forms'>
<SimpleForm renderBoth={renderBoth}/>
</div>
<button
type='button'
onClick={this.handleClick}>
{renderBoth ? 'Show Single' : 'Show Both'}
</button>
</div>
);
}
Updated example
SOLUTION 1
I was having interference with invalid and valid props of the Redux Form because I wrote the validate function on ReduxForm() in every file of my main form component.
You haven't to change the form name to solve this. You have to put the validation function on the parent component.
Here is an example:
[CONTEXT]
I have 3 Components:
1. Main component to put the form ('editUserForm') elements (, , ...)
2. Field1 of the form ('editUserForm') that changes user's complete name.
3. Field2 of the form ('editUserForm') that changes user's email.
[SOLUTION]
MAIN COMPONENT:
Inside the main frame, you call reduxForm() (it creates a decorator with which you use redux-form to connect your form component to Redux. More info here Redux Form docs). Your code would be like this:
import...
class MainFrame ... {
...
<form ...>
<Field1 />
<Field2 />
</form>
...
}
const validate ({ name, email }, props) => {
errors={}
// Validation around Field1
if (name === ...) errors.name = "Name error passed to Field1 component";
// Validation around Field2
if (email === ...) errors.email= "Email error passed to Field2 component";
return errors;
}
...
export default reduxForm({
form: 'editUserForm',
validate // <--------- IMPORTANT: Only put this function on the parent component.
})(MainComponent);
FIELD1 & FIELD2 COMPONENTS:
This code is for the 2 children components. IMPORTANT: You call reduxForm() without validate Redux Form docs synchronous function.
import...
class MainFrame ... {
...
const { invalid } = this.props;
...
<inputs
error={invalid}
>
...
</input>
...
}
// IMPORTANT: Don't put the validation function in Field1 and Field2 components, because their local validations will interfere with the validation of the other Field component.
reduxForm({
form: 'editUserForm'
})
Now, the props: valid and invalid will work perfectly inside the children components (Field1 and Field2).
SOLUTION 2
User Redux Form FormSection (docs) to split forms into smaller components that are reusable across multiple forms.
In my project we are building a form with React and Redux-Form. We have a single information that is composed by the value of two inputs. But the values of each input is combined and validated together.
The first implementation try was by connecting each component with Field. It let us update the state properly but we couldn't validate all the values together with the validate prop.
The second Try was using Fieldscomponent but it does not have a validate prop. We thought in create a Pull Request for it but the API for it isn't clear yet, since what we want to validate the combination of the two values and the behavior of the Fields props (such as parse and format) is different, executing the function for each input inside Fields component separately.
I know it is possible to create a component and use Field to connect with the application state, but I didn't want to manage things as the touched prop, or the callbacks to update the state, or other things that I even have noticed, since Redux-Form has all of it done.
The fact is that I end up with an implementation but it didn't looked very elegant. I'd like you to take a look at the implementation and give your opinion, sugest other solutions and even if this solution is not implemented in Redux-Form yet we could maybe open a pull request for that.
Here is an example implementation
Simple form container
import SimpleForm from 'app/simpleForm/components/simpleForm'
import { reduxForm } from 'redux-form'
export default reduxForm({
form: 'simpleForm'
})(SimpleForm)
Simple form component
import React from 'react'
import { Field } from 'redux-form'
import MultiInputText from 'app/simpleForm/components/multiInputText'
const onSubmit = values => alert(JSON.stringify(values))
const validateAddress = (value) => {
if (!value) return 'Address is empty'
if (!value.street) return 'Street is empty'
if (!value.number) return 'Number is empty'
return null
}
const SimpleForm = ({ handleSubmit }) => {
return (
<form onSubmit={ handleSubmit(onSubmit) }>
<Field label="Home Address" name="home" component={MultiInputText} type="text" validate={validateAddress}/>
<Field label="Work Address" name="work" component={MultiInputText} type="text" validate={validateAddress}/>
<button type="submit">Submit</button>
</form>
)
}
export default SimpleForm
MultiInputText component
import React from 'react'
import { Fields, FormSection } from 'redux-form'
const renderAddreessInputs = ({ street, number, error }) => (<div>
<input {...street.input} type="text" />
<input {...number.input} type="text" />
{ street.meta.touched && number.meta.touched && error && <span className="error">{error}</span> }
</div>)
const MultiInputText = (props) => {
const { input: { name }, label, meta: { error }} = props
const names = [
'street',
'number'
]
return (<div>
<label htmlFor={name}>{label}</label>
<FormSection name={name}>
<Fields names={names} component={renderAddreessInputs} error={error}/>
</FormSection>
</div>)
}
export default MultiInputText
I see two options:
1) Use record-level validation.
reduxForm({
form: 'addressForm',
validate: values => {
const errors = {}
if(!home) {
errors.home = 'Address is empty'
}
// etc, etc. Could reuse same code for home and work
return errors
}
})
2) Create a single input that handles a complex value.
<Field name="home" component="AddressInput"/>
...
const AddressInput = ({ input, meta }) =>
<div>
<input
name={`${input.name}.street`}
value={(input.value && input.value.street) || ''}
onChange={event => input.onChange({
...input.value,
street: event.target.value
})}/>
...other inputs here...
</div>
That's total pseudocode, but I hope it gets the point across: a single input can edit a whole object structure.
Personally, I'd choose Option 1, but I prefer record-level validation over field-level validation in general. The nice thing about Option 2 is that a single AddressInput could be reused across the application. The downside is that you don't get specific field-level focus/blur/dirty/pristine state.
Hope that helps...?
I have a FieldArray like this:
renderLanguages = fields => (
<div>
{fields.map(fieldName => <Field name={fieldName + '.iso'} component="input" type="text" />
</div>
)
<FieldArray name="languages" component={renderLanguages} />
And i like to validate it in a async way:
const asyncValidate = values => {
console.log(values);
}
export default reduxForm({
form: 'languagesForm',
asyncValidate,
asyncBlurFields: ['languages']
})(LanguagesForm)
My asyncValidate never gets called. I wonder if i have to specify the asyncBlur fields in an other way. Or if redux-form does not provide the async validation of field arrays.
To get Redux-form FormArray working with the asyncValidate, it requires to pass the field as languages[].<nameOfTheFieldOfChildComponet> but not languages only.
I think its good design too as generally, we don't validate asynchronously on change of any parameter but a specific parameter.
Here is the working example:- https://codesandbox.io/s/mq8zz58mrj
const asyncValidate = values => {
console.log(values);
}
export default reduxForm({
form: 'languagesForm',
asyncValidate,
asyncBlurFields: ['languages[].name']
})(LanguagesForm)
I have a react-bootstrap class of a form. The code is something like that:
class MyReactClass extends Component {
// ....
render() {
return (
<div>
<Field name="combobox1" component={ComboBox} options={options} ></Field>
<Field name="textField2" component={My_TextField}></Field>
<Field name="textField3" component={My_TextField}></Field>
<Field name="textField4" component={My_TextField}></Field>
</div>
}
}
export default reduxForm({
form: 'myReactClass ',
}
)(MyReactClass );
I added an initialization to initialize some values:
componentDidMount() {
this.props.initialize({textField2:'blabla'});
}
Now I want that when the user selects a value from the combobox, it'll automatically change the value of textfield3. I have a WORKING onChange function for the combobox, but I can't find a way to change textfield3's value. I tried to use "initialize" again -
this.props.initialize({textField3: this.getUpdatedValue()});
but it initialize the whole form and the form gets cleared and have only the value for textfield3.
I tried to access this.props.textField3 but I got undefined.
How can I update the form's value?
this.props.change('textField3', this.getUpdatedValue()) would work.
Optionally, if you need the user to understand that the value was autofilled but can be manually changed, you can use:
this.props.autofill('textField3', this.getUpdatedValue())
These are described in the docs here.