yunxiao-form-native
v0.0.2
Published
react-native powered UI library for developing forms writing less code
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Maintainers
Readme
Setup
npm install tcomb-form-native
Supported react-native versions
- tcomb-form-native ^0.4: react-native >= 0.20.0
- tcomb-form-native ^0.3: react-native < 0.13.0
Domain Driven Forms
The tcomb library provides a concise but expressive way to define domain models in JavaScript.
The tcomb-validation library builds on tcomb, providing validation functions for tcomb domain models.
This library builds on those two and the awesome react-native.
Benefits
With tcomb-form-native you simply call <Form type={Model} />
to generate a form based on that domain model. What does this get you?
- Write a lot less code
- Usability and accessibility for free (automatic labels, inline validation, etc)
- No need to update forms when domain model changes
JSON Schema support
JSON Schemas are also supported via the (tiny) tcomb-json-schema library.
Pluggable look and feel
The look and feel is customizable via react-native stylesheets and templates (see documentation).
Screencast
http://react.rocks/example/tcomb-form-native
Example App
https://github.com/bartonhammond/snowflake React-Native, Tcomb, Redux, Parse.com, Jest - 88% coverage
Example
// index.ios.js
'use strict';
var React = require('react-native');
var t = require('tcomb-form-native');
var { AppRegistry, StyleSheet, Text, View, TouchableHighlight } = React;
var Form = t.form.Form;
// here we are: define your domain model
var Person = t.struct({
name: t.String, // a required string
surname: t.maybe(t.String), // an optional string
age: t.Number, // a required number
rememberMe: t.Boolean // a boolean
});
var options = {}; // optional rendering options (see documentation)
var AwesomeProject = React.createClass({
onPress: function () {
// call getValue() to get the values of the form
var value = this.refs.form.getValue();
if (value) { // if validation fails, value will be null
console.log(value); // value here is an instance of Person
}
},
render: function() {
return (
<View style={styles.container}>
{/* display */}
<Form
ref="form"
type={Person}
options={options}
/>
<TouchableHighlight style={styles.button} onPress={this.onPress} underlayColor='#99d9f4'>
<Text style={styles.buttonText}>Save</Text>
</TouchableHighlight>
</View>
);
}
});
var styles = StyleSheet.create({
container: {
justifyContent: 'center',
marginTop: 50,
padding: 20,
backgroundColor: '#ffffff',
},
title: {
fontSize: 30,
alignSelf: 'center',
marginBottom: 30
},
buttonText: {
fontSize: 18,
color: 'white',
alignSelf: 'center'
},
button: {
height: 36,
backgroundColor: '#48BBEC',
borderColor: '#48BBEC',
borderWidth: 1,
borderRadius: 8,
marginBottom: 10,
alignSelf: 'stretch',
justifyContent: 'center'
}
});
AppRegistry.registerComponent('AwesomeProject', () => AwesomeProject);
Output:
(Labels are automatically generated)
Ouput after a validation error:
API
getValue()
Returns null
if the validation failed, an instance of your model otherwise.
Note. Calling
getValue
will cause the validation of all the fields of the form, including some side effects like highlighting the errors.
validate()
Returns a ValidationResult
(see tcomb-validation for a reference documentation).
Adding a default value and listen to changes
The Form
component behaves like a controlled component:
var Person = t.struct({
name: t.String,
surname: t.maybe(t.String)
});
var AwesomeProject = React.createClass({
getInitialState() {
return {
value: {
name: 'Giulio',
surname: 'Canti'
}
};
},
onChange(value) {
this.setState({value});
},
onPress: function () {
var value = this.refs.form.getValue();
if (value) {
console.log(value);
}
},
render: function() {
return (
<View style={styles.container}>
<Form
ref="form"
type={Person}
value={this.state.value}
onChange={this.onChange}
/>
<TouchableHighlight style={styles.button} onPress={this.onPress} underlayColor='#99d9f4'>
<Text style={styles.buttonText}>Save</Text>
</TouchableHighlight>
</View>
);
}
});
The onChange
handler has the following signature:
(raw: any, path: Array<string | number>) => void
where
raw
contains the current raw value of the form (can be an invalid value for your model)path
is the path to the field triggering the change
Warning. tcomb-form-native uses
shouldComponentUpdate
aggressively. In order to ensure that tcomb-form-native detect any change totype
,options
orvalue
props you have to change references:
Disable a field based on another field's value
var Type = t.struct({
disable: t.Boolean, // if true, name field will be disabled
name: t.String
});
// see the "Rendering options" section in this guide
var options = {
fields: {
name: {}
}
};
var AwesomeProject = React.createClass({
getInitialState() {
return {
options: options,
value: null
};
},
onChange(value) {
// tcomb immutability helpers
// https://github.com/gcanti/tcomb/blob/master/GUIDE.md#updating-immutable-instances
var options = t.update(this.state.options, {
fields: {
name: {
editable: {'$set': !value.disable}
}
}
});
this.setState({options: options, value: value});
},
onPress: function () {
var value = this.refs.form.getValue();
if (value) {
console.log(value);
}
},
render: function() {
return (
<View style={styles.container}>
<Form
ref="form"
type={Type}
options={this.state.options}
value={this.state.value}
onChange={this.onChange}
/>
<TouchableHighlight style={styles.button} onPress={this.onPress} underlayColor='#99d9f4'>
<Text style={styles.buttonText}>Save</Text>
</TouchableHighlight>
</View>
);
}
});
How to get access to a field
You can get access to a field with the getComponent(path)
API:
var Person = t.struct({
name: t.String,
surname: t.maybe(t.String),
age: t.Number,
rememberMe: t.Boolean
});
var AwesomeProject = React.createClass({
componentDidMount() {
// give focus to the name textbox
this.refs.form.getComponent('name').refs.input.focus();
},
onPress: function () {
var value = this.refs.form.getValue();
if (value) {
console.log(value);
}
},
render: function() {
return (
<View style={styles.container}>
<Form
ref="form"
type={Person}
/>
<TouchableHighlight style={styles.button} onPress={this.onPress} underlayColor='#99d9f4'>
<Text style={styles.buttonText}>Save</Text>
</TouchableHighlight>
</View>
);
}
});
How to clear form after submit
var Person = t.struct({
name: t.String,
surname: t.maybe(t.String),
age: t.Number,
rememberMe: t.Boolean
});
var AwesomeProject = React.createClass({
getInitialState() {
return { value: null };
},
onChange(value) {
this.setState({ value });
},
clearForm() {
// clear content from all textbox
this.setState({ value: null });
},
onPress: function () {
var value = this.refs.form.getValue();
if (value) {
console.log(value);
// clear all fields after submit
this.clearForm();
}
},
render: function() {
return (
<View style={styles.container}>
<Form
ref="form"
type={Person}
value={this.state.value}
onChange={this.onChange.bind(this)}
/>
<TouchableHighlight style={styles.button} onPress={this.onPress} underlayColor='#99d9f4'>
<Text style={styles.buttonText}>Save</Text>
</TouchableHighlight>
</View>
);
}
});
Dynamic forms example: how to change a form based on selection
Say I have an iospicker, depending on which option is selected in this picker I want the next component to either be a checkbox or a textbox:
const Country = t.enums({
'IT': 'Italy',
'US': 'Unisted States'
}, 'Country');
var AwesomeProject = React.createClass({
// returns the suitable type based on the form value
getType(value) {
if (value.country === 'IT') {
return t.struct({
country: Country,
rememebrMe: t.Boolean
});
} else if (value.country === 'US') {
return t.struct({
country: Country,
name: t.String
});
} else {
return t.struct({
country: Country
});
}
},
getInitialState() {
const value = {};
return { value, type: this.getType(value) };
},
onChange(value) {
// recalculate the type only if strictly necessary
const type = value.country !== this.state.value.country ?
this.getType(value) :
this.state.type;
this.setState({ value, type });
},
onPress() {
var value = this.refs.form.getValue();
if (value) {
console.log(value);
}
},
render() {
return (
<View style={styles.container}>
<t.form.Form
ref="form"
type={this.state.type}
value={this.state.value}
onChange={this.onChange}
/>
<TouchableHighlight style={styles.button} onPress={this.onPress} underlayColor='#99d9f4'>
<Text style={styles.buttonText}>Save</Text>
</TouchableHighlight>
</View>
);
}
});
Types
Required field
By default fields are required:
var Person = t.struct({
name: t.String, // a required string
surname: t.String // a required string
});
Optional field
In order to create an optional field, wrap the field type with the t.maybe
combinator:
var Person = t.struct({
name: t.String,
surname: t.String,
email: t.maybe(t.String) // an optional string
});
The postfix " (optional)"
is automatically added to optional fields.
You can customise the postfix value or setting a postfix for required fields:
t.form.Form.i18n = {
optional: '',
required: ' (required)' // inverting the behaviour: adding a postfix to the required fields
};
Numbers
In order to create a numeric field, use the t.Number
type:
var Person = t.struct({
name: t.String,
surname: t.String,
email: t.maybe(t.String),
age: t.Number // a numeric field
});
tcomb-form-native will convert automatically numbers to / from strings.
Booleans
In order to create a boolean field, use the t.Boolean
type:
var Person = t.struct({
name: t.String,
surname: t.String,
email: t.maybe(t.String),
age: t.Number,
rememberMe: t.Boolean // a boolean field
});
Booleans are displayed as SwitchIOS
s.
Dates
In order to create a date field, use the t.Date
type:
var Person = t.struct({
name: t.String,
surname: t.String,
email: t.maybe(t.String),
age: t.Number,
birthDate: t.Date // a date field
});
Dates are displayed as DatePickerIOS
s under iOS and DatePickerAndroid
or TimePickerAndroid
under Android, depending on the mode
selected (date
or time
).
Android date config
option
When using a t.Date
type in Android, it can be configured through a config
option that take the following parameters:
| Key | Value |
|-----|-------|
| background
| Determines the type of background drawable that's going to be used to display feedback. Optional, defaults to TouchableNativeFeedback.SelectableBackground
. |
| format
| A (date) => String(date)
kind of function to provide a custom date format parsing to display the value. Optional, defaults to (date) => String(date)
.
Enums
In order to create an enum field, use the t.enums
combinator:
var Gender = t.enums({
M: 'Male',
F: 'Female'
});
var Person = t.struct({
name: t.String,
surname: t.String,
email: t.maybe(t.String),
age: t.Numner,
rememberMe: t.Boolean,
gender: Gender // enum
});
Enums are displayed as Picker
s.
Refinements
A predicate is a function with the following signature:
(x: any) => boolean
You can refine a type with the t.refinement(type, predicate)
combinator:
// a type representing positive numbers
var Positive = t.refinement(t.Number, function (n) {
return n >= 0;
});
var Person = t.struct({
name: t.String,
surname: t.String,
email: t.maybe(t.String),
age: Positive, // refinement
rememberMe: t.Boolean,
gender: Gender
});
Subtypes allow you to express any custom validation with a simple predicate.
Rendering options
In order to customize the look and feel, use an options
prop:
<Form type={Model} options={options} />
Form component
Labels and placeholders
By default labels are automatically generated. You can turn off this behaviour or override the default labels on field basis.
var options = {
label: 'My struct label' // <= form legend, displayed before the fields
};
var options = {
fields: {
name: {
label: 'My name label' // <= label for the name field
}
}
};
In order to automatically generate default placeholders, use the option auto: 'placeholders'
:
var options = {
auto: 'placeholders'
};
<Form type={Person} options={options} />
Set auto: 'none'
if you don't want neither labels nor placeholders.
var options = {
auto: 'none'
};
Fields order
You can sort the fields with the order
option:
var options = {
order: ['name', 'surname', 'rememberMe', 'gender', 'age', 'email']
};
Default values
You can set the default values passing a value
prop to the Form
component:
var value = {
name: 'Giulio',
surname: 'Canti',
age: 41,
gender: 'M'
};
<Form type={Model} value={value} />
Fields configuration
You can configure each field with the fields
option:
var options = {
fields: {
name: {
// name field configuration here..
},
surname: {
// surname field configuration here..
}
}
};
Textbox component
Implementation: TextInput
Tech note. Values containing only white spaces are converted to null
.
Placeholder
You can set the placeholder with the placeholder
option:
var options = {
fields: {
name: {
placeholder: 'Your placeholder here'
}
}
};
Label
You can set the label with the label
option:
var options = {
fields: {
name: {
label: 'Insert your name'
}
}
};
Help message
You can set a help message with the help
option:
var options = {
fields: {
name: {
help: 'Your help message here'
}
}
};
Error messages
You can add a custom error message with the error
option:
var options = {
fields: {
email: {
// you can use strings or JSX
error: 'Insert a valid email'
}
}
};
tcomb-form-native will display the error message when the field validation fails.
error
can also be a function with the following signature:
(value, path, context) => ?(string | ReactElement)
where
value
is an object containing the current form value.path
is the path of the value being validatedcontext
is the value of thecontext
prop. Also it contains a reference to the component options.
The value returned by the function will be used as error message.
If you want to show the error message onload, add the hasError
option:
var options = {
hasError: true,
error: <i>A custom error message</i>
};
Another way is to add a:
getValidationErrorMessage(value, path, context)
static function to a type, where:
value
is the (parsed) current value of the component.path
is the path of the value being validatedcontext
is the value of thecontext
prop. Also it contains a reference to the component options.
var Age = t.refinement(t.Number, function (n) { return n >= 18; });
// if you define a getValidationErrorMessage function, it will be called on validation errors
Age.getValidationErrorMessage = function (value, path, context) {
return 'bad age, locale: ' + context.locale;
};
var Schema = t.struct({
age: Age
});
...
<t.form.Form
ref="form"
type={Schema}
context={{locale: 'it-IT'}}
/>
You can even define getValidationErrorMessage
on the supertype in order to be DRY:
t.Number.getValidationErrorMessage = function (value, path, context) {
return 'bad number';
};
Age.getValidationErrorMessage = function (value, path, context) {
return 'bad age, locale: ' + context.locale;
};
Other standard options
The following standard options are available (see http://facebook.github.io/react-native/docs/textinput.html):
autoCapitalize
autoCorrect
autoFocus
bufferDelay
clearButtonMode
editable
enablesReturnKeyAutomatically
keyboardType
maxLength
multiline
numberOfLines
onBlur
onEndEditing
onFocus
onSubmitEditing
password
placeholderTextColor
returnKeyType
selectTextOnFocus
secureTextEntry
selectionState
textAlign
textAlignVertical
underlineColorAndroid
Checkbox component
Implementation: SwitchIOS
The following options are similar to the Textbox
component's ones:
label
help
error
Other standard options
The following standard options are available (see http://facebook.github.io/react-native/docs/switchios.html):
disabled
onTintColor
thumbTintColor
tintColor
Select component
Implementation: PickerIOS
The following options are similar to the Textbox
component's ones:
label
help
error
nullOption
option
You can customize the null option with the nullOption
option:
var options = {
fields: {
gender: {
nullOption: {value: '', label: 'Choose your gender'}
}
}
};
You can remove the null option setting the nullOption
option to false
.
Warning: when you set nullOption = false
you must also set the Form's value
prop for the select field.
Tech note. A value equal to nullOption.value
(default ''
) is converted to null
.
Options order
You can sort the options with the order
option:
var options = {
fields: {
gender: {
order: 'asc' // or 'desc'
}
}
};
DatePicker component
Implementation: DatePickerIOS
Example
var Person = t.struct({
name: t.String,
birthDate: t.Date
});
The following options are similar to the Textbox
component's ones:
label
help
error
Other standard options
The following standard options are available (see http://facebook.github.io/react-native/docs/datepickerios.html):
maximumDate
,minimumDate
,minuteInterval
,mode
,timeZoneOffsetInMinutes
Customizations
Stylesheets
See also Stylesheet guide.
tcomb-form-native comes with a default style. You can customize the look and feel by setting another stylesheet:
var t = require('tcomb-form-native/lib');
var i18n = require('tcomb-form-native/lib/i18n/en');
var templates = require('tcomb-form-native/lib/templates/bootstrap');
// define a stylesheet (see lib/stylesheets/bootstrap for an example)
var stylesheet = {...};
// override globally the default stylesheet
t.form.Form.stylesheet = stylesheet;
// set defaults
t.form.Form.templates = templates;
t.form.Form.i18n = i18n;
You can also override the stylesheet locally for selected fields:
var Person = t.struct({
name: t.String
});
var options = {
fields: {
name: {
stylesheet: myCustomStylesheet
}
}
};
Or per form:
var Person = t.struct({
name: t.String
});
var options = {
stylesheet: myCustomStylesheet
};
For a complete example see the default stylesheet https://github.com/gcanti/tcomb-form-native/blob/master/lib/stylesheets/bootstrap.js.
Templates
tcomb-form-native comes with a default layout, i.e. a bunch of templates, one for each component. When changing the stylesheet is not enough, you can customize the layout by setting custom templates:
var t = require('tcomb-form-native/lib');
var i18n = require('tcomb-form-native/lib/i18n/en');
var stylesheet = require('tcomb-form-native/lib/stylesheets/bootstrap');
// define the templates (see lib/templates/bootstrap for an example)
var templates = {...};
// override globally the default layout
t.form.Form.templates = templates;
// set defaults
t.form.Form.stylesheet = stylesheet;
t.form.Form.i18n = i18n;
You can also override the template locally:
var Person = t.struct({
name: t.String
});
function myCustomTemplate(locals) {
var containerStyle = {...};
var labelStyle = {...};
var textboxStyle = {...};
return (
<View style={containerStyle}>
<Text style={labelStyle}>{locals.label}</Text>
<TextInput style={textboxStyle} />
</View>
);
}
var options = {
fields: {
name: {
template: myCustomTemplate
}
}
};
A template is a function with the following signature:
(locals: Object) => ReactElement
where locals
is an object contaning the "recipe" for rendering the input and it's built for you by tcomb-form-native.
Let's see an example: the locals
object passed in the checkbox
template:
type Message = string | ReactElement
{
stylesheet: Object, // the styles to be applied
hasError: boolean, // true if there is a validation error
error: ?Message, // the optional error message to be displayed
label: Message, // the label to be displayed
help: ?Message, // the optional help message to be displayed
value: boolean, // the current value of the checkbox
onChange: Function, // the event handler to be called when the value changes
config: Object, // an optional object to pass configuration options to the new template
...other input options here...
}
For a complete example see the default template https://github.com/gcanti/tcomb-form-native/blob/master/lib/templates/bootstrap.
i18n
tcomb-form-native comes with a default internationalization (English). You can customize the look and feel by setting another i18n:
var t = require('tcomb-form-native/lib');
var templates = require('tcomb-form-native/lib/templates/bootstrap');
// define a stylesheet (see tcomb-form-native/lib/i18n/en for an example)
var i18n = {...};
// override globally the default i18n
t.form.Form.i18n = i18n;
// set defaults
t.form.Form.templates = templates;
t.form.Form.stylesheet = stylesheet;
Transformers
Say you want a search textbox which accepts a list of keywords separated by spaces:
var Search = t.struct({
search: t.list(t.String)
});
tcomb-form by default will render the search
field as a list. In order to render a textbox you have to override the default behaviour with the factory option:
var options = {
fields: {
search: {
factory: t.form.Textbox
}
}
};
There is a problem though: a textbox handle only strings so we need a way to transform a list in a string and a string in a list: a Transformer
deals with serialization / deserialization of data and has the following interface:
var Transformer = t.struct({
format: t.Function, // from value to string, it must be idempotent
parse: t.Function // from string to value
});
A basic transformer implementation for the search textbox:
var listTransformer = {
format: function (value) {
return Array.isArray(value) ? value.join(' ') : value;
},
parse: function (str) {
return str ? str.split(' ') : [];
}
};
Now you can handle lists using the transformer option:
// example of initial value
var value = {
search: ['climbing', 'yosemite']
};
var options = {
fields: {
search: {
factory: t.form.Textbox, // tell tcomb-react-native to use the same component for textboxes
transformer: listTransformer,
help: 'Keywords are separated by spaces'
}
}
};
Custom factories
You can pack together style, template (and transformers) in a custom component and then you can use it with the factory
option:
var Component = t.form.Component;
// extend the base Component
class MyComponent extends Component {
// this is the only required method to implement
getTemplate() {
// define here your custom template
return function (locals) {
//return ... jsx ...
};
}
// you can optionally override the default getLocals method
// it will provide the locals param to your template
getLocals() {
// in locals you'll find the default locals:
// - path
// - error
// - hasError
// - label
// - onChange
// - stylesheet
var locals = super.getLocals();
// add here your custom locals
return locals;
}
}
// as example of transformer: this is the default transformer for textboxes
MyComponent.transformer = {
format: value => Nil.is(value) ? null : value,
parse: value => (t.String.is(value) && value.trim() === '') || Nil.is(value) ? null : value
};
var Person = t.struct({
name: t.String
});
var options = {
fields: {
name: {
factory: MyComponent
}
}
};
Tests
npm test
License
MIT