react-formo
v0.2.1
Published
Formo ~ another form state management for React
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Readme
formo
Form state management
Usage (basic example)
import formo from 'formo'
const MyFormoComponent = formo(
class MyFC extends React.Component {
render() {
const {
email, password,
form: { isValid, isChanged }
} = this.props
const submitEnabled = isChanged && isValid
return (
<div>
<input
type='email'
value={email.value || ''}
onChange={e => email.update(e.target.value)}
/>
{email.touched && email.validationErrors.map(error => (
<div className='error'>{error}</div>
)}
<input
type='password'
value={password.value || ''}
onChange={e => password.update(e.target.value)}
/>
<input type='submit' value='submit' disabled={!submitEnabled} />
</div>
)
}
}
)
const fields = {
email: {},
password: {}
}
const validations = {
email: {
invalidEmail: v => validEmailRegex.test(v)
}
}
export default class MyComponent {
render() {
return <MyFormoComponent fields={fields} validations={validations} />
}
}
Motivation and guiding principles
- avoid repeating common tasks among different form, such as validation logic, computing "dirtiness" state, enabling submit button, showing errors only if X, etc.
- it should be independent from rendering (not tied to a specific set of UI components)
- it should be independent from the state management framework (not tied to redux, mobx, etc.)
- it should be easy to use as-is, as a stateful component, and easy to integrate with any state management framework
API
Create a "formo component"
import formo from 'formo'
class MyComponent extends React.Component {
// ...
}
export default formo(MyComponent)
From this component, you'll have access to the complete form state via props. This includes current values, validity, and other useful meta info such as "touched", "changed", etc. See a comprehensive list in the tables below.
configure a "formo component"
A "formo component" can be configured through props with a set of fields and validations to apply.
import MyFormoComponent from './MyFormoComponent'
// ...
render() {
// `validations` and `onChange` are optional
return (
<MyFormoComponent
fields={fields}
validations={validations}
onChange={onChange}
/>
)
}
// ...
props
API
name | required | type | description
---|---|---|---
fields | required | dict(FieldName, Field)
| Configure form fields
validations | | dict(FieldNameOrForm, dict(validationName, Validations))
| Optionally configure form-level and field-level validations
onChange | | function<Value>
| Optionally provide an onChange
callback, will be called with the new values after every change
FieldName
: a string representing a field, e.g. "email".
Field
: an object in the form:
{
value: any,
initialValue: any,
active: ?boolean,
touched: ?boolean
}
FieldNameOrForm = FieldName | 'form'
: form-level validations are specified using the special string "form".
Validations
: a dict(string, function)
with each function, returning a Boolean.
Each function is called with two arguments (field value
and all form values
) if applied to a field, with a single value (all form values
) if it is applied at form-level.
In other words, a validation function should be treated like a test that the field or the form should pass.
formo
will list the failed validation
function names in the validationErrors
array.
Validity for single fields and for the global form is computed based on presence (absence) of these errors.
fields
example
fields = {
email: {
value: cookie.email
},
password: {},
repeatPassword: {},
foo: {
initialValue: true
},
bar: {
initialValue: false
}
}
validations
example
validations = {
password: {
minLength: value => value.length > 8,
numeric: value => value.test(/\d/)
},
repeatPassword: {
passwordMatch: (repeatPassword, { password }) => repeatPassword === password
},
form: {
atLestOneFooOrBar: values => !value.foo && !value.bar
}
}
Use form values from a "formo component"
Formo component props api
A formo component receives via props:
- form-level values and derived properties, via the
form
prop - for each field, field-level value and derived properties, via the
[field]
prop.
Form-level props
type | name/usage | description
---|---|---
function
| form.clearValues()
| Sets every field value in the form to field.initialValue || undefined
. The input below should be aware and handle undefined
as controlled anyway.
function
| form.touchAll()
| Sets every field as "touched". Useful if we have a validation UI rendering logic similar to touched && errors && renderErrors()
and we want to force errors rendering after a certain event (e.g. user clicks on "submit")
boolean
| form.isChanged
| Is any field changed?
boolean
| form.isValid
| Is the form as a whole "valid" (no validation errors)?
list(string)
| form.validationErrors
| validations failing
Form-level prop usage example
// ...
render() {
const submitEnabled = this.props.form.isValid && this.props.form.isChanged;
const errors = map(this.props.form.validations, err => <Error>{err}</Error>)
return (
// ...
{errors}
<input type='submit' value='Submit' disabled={!submitEnabled} />
// ...
)
}
// ...
Field-level props
type | name/usage | description
---|---|---
any
| [field].value
| Always == value || initialValue || undefined
. The input below should be aware and handle undefined
as controlled anyway
any
| [field].initialValue
| initialValue
provided in form config for the field, if any
function(any)
| [field].update(newValue)
| Updates a field value. Typically passed to an input onChange
boolean
| [field].active
| Whether the field is currently "active". It is guaranteed to be exclusive (a single field is active at any time. If multiple fields are marked as "active" in config, only the first one is considered active)
function
| [field].setActive()
| Set the field as "active"
function
| [field].unsetActive()
| Set the field as "non active". Also updates touched
accordingly
boolean
| [field].touched
| true
if input has been unsetActive()
in the past (typically after a blur, or, as always, if the field is configured as touched=true
in config)
function
| [field].clear()
| Set field value
to initialValue || undefined
boolean
| [field].isChanged
| true
if input value
is the same as initialValue
(or "adequately equal")
list(string)
| form.validationErrors
| validations failing
any
| [field].[<any other key>]
| Any other field key provided in form config is just passed down
function(string, any)
| [field].set('prop', value)
| Any other field key can be changed using .set
Field-level prop usage example
// ...
render() {
const email = this.props.email;
const className = cx({
active: email.active,
error: email.touched && !email.isValid
})
return (
<input
type='email'
value={email.value || ''}
className={className}
onFocus={email.setActive}
onBlur={email.unsetActive}
onChange={e => email.update(e.target.value)}
/>
)
}
// ...