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Form component provides a way to build simple forms at Grafana. It is built on top of react-hook-form library and incorporates the same concepts while adjusting the API slightly.
Note: This component is deprecated and will be removed in the future versions of grafana/ui. Use the useForm
hook from react-hook-form instead.
import { Forms } from '@grafana/ui'; interface UserDTO { name: string; email: string; //... } const defaultUser: Partial<UserDTO> = { name: 'Roger Waters', // ... } <Form defaultValues={defaultUser} onSubmit={async (user: UserDTO) => await createUser(user)} >{({register, errors}) => { return ( <Field> <Input {...register("name")}/> <Input {...register("email", {required: true})} type="email" /> <Button type="submit">Create User</Button> </Field> ) }}</Form>
Form
component exposes API via render prop. Three properties are exposed: register
, errors
and control
register
register
allows registering form elements (inputs, selects, radios, etc) in the form. In order to do that you need to invoke the function itself and spread the props into the input. For example:
<Input {...register('inputName')} />
The first argument for register
is the field name. It also accepts an object, which describes validation rules for a given input:
<Input {...register("inputName", { required: true, minLength: 10, validate: v => { // custom validation rule } })} />
See Validation for examples on validation and validation rules.
errors
errors
is an object that contains validation errors of the form. To show error message and invalid input indication in your form, wrap input element with <Field ...>
component and pass invalid
and error
props to it:
<Field label="Name" invalid={!!errors.name} error="Name is required"> <Input {...register('name', { required: true })} /> </Field>
control
By default Form
component assumes form elements are uncontrolled (https://reactjs.org/docs/glossary.html#controlled-vs-uncontrolled-components).
There are some components like RadioButton
or Select
that are controlled-only and require some extra work. To make
them work with the form, you need to render those using InputControl
component:
import { Form, Field, InputControl } from '@grafana/ui'; // render function <Form ...>{({register, errors, control}) => ( <> <Field label="RadioButtonExample"> <InputControl {/* Render InputControl as controlled input (RadioButtonGroup) */} render={({field}) => <RadioButtonGroup {...field} options={...} />} {/* Pass control exposed from Form render prop */} control={control} name="radio" /> </Field> <Field label="SelectExample"> <InputControl {/* Render InputControl as controlled input (Select) */} render={({field}) => <Select {...field} options={...} />} {/* Pass control exposed from Form render prop */} control={control} name="select" /> </Field> </> )} </Form>
In case we want to modify the selected value before passing it to the form, we can use the onChange
callback from the render's field
argument:
<Field label="SelectExample"> <InputControl {/* Here `value` has a nested `value` property, which we want to save onto the form. */} render={(field: {onChange, ...field}) => <Select {...field} onChange={(value) => onChange(value.value)}/>} control={control} name="select" /> </Field>
Note that field
also contains ref
prop, which is passed down to the rendered component by default. In case if that component doesn't support this prop, it will need to be removed before spreading the field
.
<Field label="SelectExample"> <InputControl {/*Remove `ref` prop, so it doesn't get passed down to the component that doesn't support it. */} render={(field: {onChange, ref, ...field}) => <Select {...field} onChange={(value) => onChange(value.value)}/>} control={control} name="select" /> </Field>
Default values of the form can be passed either via defaultValues
property on the Form
element, or directly on
form's input via defaultValue
prop.
Note that changing/updating defaultValues
passed to the form will reset the form's state, which might be undesirable in
case it has both controlled and uncontrolled components. In that case it's better to pass defaultValue
to each form component separately.
// Passing default values to the Form interface FormDTO { name: string; isAdmin: boolean; } const defaultValues: FormDto { name: 'Roger Waters', isAdmin: false, } <Form defaultValues={defaultValues} ...>{...}</Form>
// Passing default value directly to form inputs interface FormDTO { name: string; isAdmin: boolean; } const defaultValues: FormDto { name: 'Roger Waters', isAdmin: false, } <Form ...>{ ({register}) => ( <> <Input {...register("name")} defaultValue={default.name} /> </> )} </Form>
Validation can be performed either synchronously or asynchronously. What's important here is that the validation function must return either a boolean
or a string
.
<Form ...>{ ({register, errors}) => ( <> <Field invalid={!!errors.name} error={errors.name && 'Name is required'} <Input {...register("name", { required: true })} defaultValue={default.name} /> </> )} </Form>
One important thing to note is that if you want to provide different error messages for different kind of validation errors you'll need to return a string
instead of a boolean
.
<Form ...>{ ({register, errors}) => ( <> <Field invalid={!!errors.name} error={errors.name?.message } <Input defaultValue={default.name} {...register("name", { required: 'Name is required', validation: v => { return v !== 'John' && 'Name must be John' }, )} /> </> )} </Form>
For cases when you might want to validate fields asynchronously (on the backend or via some service) you can provide an asynchronous function to the field.
Consider this function that simulates a call to some service. Remember, if you want to display an error message replace return true
or return false
with return 'your error message'
.
validateAsync = (newValue: string) => { try { (await new Promise()) < ValidateResult > ((resolve, reject) => { setTimeout(() => { reject('Something went wrong...'); }, 2000); }); return true; } catch (e) { return false; } };
<Form ...>{ ({register, errors}) => ( <> <Field invalid={!!errors.name} error={errors.name?.message} <Input defaultValue={default.name} {...register("name", { required: 'Name is required', validation: async v => { return await validateAsync(v); }, )} /> </> )} </Form>
Version 8 of Grafana-UI is using version 7 of react-hook-form
(previously version 5 was used), which introduced a few breaking changes to the Form
API. The detailed list of changes can be found in the library's migration guides:
In a nutshell, the two most important changes are:
ref
, but instead its result is spread onto the input component:-(<input ref={register({ required: true })} name="test" />) + <input {...register('test', { required: true })} />;
InputControl
's as
prop has been replaced with render
, which has field
and fieldState
objects as arguments. onChange
, onBlur
, value
, name
, and ref
are parts of field
.- <Controller as={<input />} /> + <Controller render={({ field }) => <input {...field} />} // or + <Controller render={({ field, fieldState }) => <input {...field} />} />
Name | Description | Default |
---|---|---|
validateOn | "onChange""onBlur""onSubmit""all""onTouched" | "onSubmit" |
validateOnMount | boolean | false |
validateFieldsOnMount | string | string[] | - |
defaultValues | { [x: string]: any; } | ((BrowserNativeObject | NestedValue) & FieldValues) | { [x: string]: any; } | - |
onSubmit* | SubmitHandler<T> | - |
maxWidth | Sets max-width for container. Use it instead of setting individual widths on inputs. number"none" | 600 |