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A simple React component capable of building HTML forms out of a JSON schema.


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Note: this is a version of react-jsonschema-form that is forked at 0.43 and further modified. If you found this unintentionally, you probably want to use https://github.com/mozilla-services/react-jsonschema-form


A simple React component capable of building HTML forms out of a JSON schema and using Bootstrap semantics by default.

Table of Contents


Requires React 15.0.0+.

Note: The master branch of the repository reflects ongoing development. Releases are published as tags.

You should never blindly install from master, but rather check what the available stable releases are.

As a npm-based project dependency

$ npm install react-jsonschema-form --save

Note: While the library renders Bootstrap HTML semantics, you have to build/load the Bootstrap styles on your own.

As a script served from a CDN

<script src="https://unpkg.com/react-jsonschema-form/dist/react-jsonschema-form.js"></script>

Source maps are available at this url.

Note: The CDN version does not embed react nor react-dom.

You'll also need to alias the default export property to use the Form component:

const Form = JSONSchemaForm.default; // or const {default: Form} = JSONSchemaForm;


import React, { Component } from "react"; import { render } from "react-dom"; import Form from "react-jsonschema-form"; const schema = { title: "Todo", type: "object", required: ["title"], properties: { title: {type: "string", title: "Title", default: "A new task"}, done: {type: "boolean", title: "Done?", default: false} } }; const log = (type) => console.log.bind(console, type); render(( <Form schema={schema} onChange={log("changed")} onSubmit={log("submitted")} onError={log("errors")} /> ), document.getElementById("app"));

That should give something like this (if you took care of loading the standard Bootstrap stylesheet):

Form initialization

Often you'll want to prefill a form with existing data; this is done by passing a formData prop object matching the schema:

const formData = { title: "First task", done: true }; render(( <Form schema={schema} formData={formData} ), document.getElementById("app"));

NOTE: If your form have a single field, pass a single value to formData. ex: formData='Charlie'

WARNING: If you have situations where your parent component can re-render, make sure you listen to the onChange event and update the data you pass to the formData attribute.

Form event handlers

Form submission

You can pass a function as the onSubmit prop of your Form component to listen to when the form is submitted and its data are valid. It will be passed a result object having a formData attribute, which is the valid form data you're usually after:

const onSubmit = ({formData}) => console.log("yay I'm valid!"); render(( <Form schema={schema} onSubmit={onSubmit} /> ), document.getElementById("app"));
Form error event handler

To react to when submitted form data are invalid, pass an onError handler, which is passed the list of encoutered errors:

const onError = (errors) => console.log("I have", errors.length, "errors to fix"); render(( <Form schema={schema} onError={onError} /> ), document.getElementById("app"));
Form data changes

If you plan on being notified everytime the form data are updated, you can pass an onChange handler, which will receive the same args as onSubmit any time a value is updated in the form.

Form field blur events

Sometimes you may want to trigger events or modify external state when a field has been touched, so you can pass an onBlur handler, which will receive the id of the input that was blurred and the field value.

Form customization

The uiSchema object

JSONSchema is limited for describing how a given data type should be rendered as a form input component, that's why this lib introduces the concept of UI schema.

A UI schema is basically an object literal providing information on how the form should be rendered, while the JSON schema tells what.

The uiSchema object follows the tree structure of the form field hierarchy, and for each allows to define how it should be rendered:

const schema = { type: "object", properties: { foo: { type: "object", properties: { bar: {type: "string"} } }, baz: { type: "array", items: { type: "object", properties: { description: { "type": "string" } } } } } } const uiSchema = { foo: { bar: { "ui:widget": "textarea" }, }, baz: { // note the "items" for an array items: { description: { "ui:widget": "textarea" } } } } render(( <Form schema={schema} uiSchema={uiSchema} /> ), document.getElementById("app"));

Alternative widgets

The uiSchema ui:widget property tells the form which UI widget should be used to render a certain field:


const uiSchema =  { done: { "ui:widget": "radio" // could also be "select" } }; render(( <Form schema={schema} uiSchema={uiSchema} formData={formData} /> ), document.getElementById("app"));

Here's a list of supported alternative widgets for different JSONSchema data types:

For boolean fields
  • radio: a radio button group with true and false as selectable values;
  • select: a select box with true and false as options;
  • by default, a checkbox is used

Note: To set the labels for a boolean field, instead of using true and false you can set enumNames in your schema. Note that enumNames belongs in your schema, not the uiSchema, and the order is always [true, false].

For string fields
  • textarea: a textarea element is used;
  • password: an input[type=password] element is used;
  • color: an input[type=color] element is used;
  • by default, a regular input[type=text] element is used.
String formats

The built-in string field also supports the JSONSchema format property, and will render an appropriate widget by default for the following string formats:

  • email: An input[type=email] element is used;
  • uri: An input[type=url] element is used;
  • data-url: By default, an input[type=file] element is used; in case the string is part of an array, multiple files will be handled automatically (see File widgets).
  • date: By default, an input[type=date] element is used;
  • date-time: By default, an input[type=datetime-local] element is used.

Please note that while standardized, datetime-local and date input elements are not yet supported by Firefox and IE. If you plan on targetting these platforms, two alternative widgets are available:

  • alt-datetime: Six select elements are used to select the year, the month, the day, the hour, the minute and the second;
  • alt-date: Three select elements are used to select the year, month and the day.

For number and integer fields
  • updown: an input[type=number] updown selector;
  • range: an input[type=range] slider;
  • radio: a radio button group with enum values. can only be used when enum values are specified for this input
  • by default, a regular input[type=text] element is used.

Note: for numbers, min, max and step input attributes values will be handled according to JSONSchema's minimum, maximium and multipleOf values when they're defined.

Disabled fields

The ui:disabled uiSchema directive will disable all child widgets from a given field.

Read-only fields

The ui:readonly uiSchema directive will mark all child widgets from a given field as read-only.

Note: if you're about the difference between a disabled field and a readonly one: marking a field as read-only will render it greyed but its text value will be selectable; disabling it will prevent its value to be selected at all.

Hidden widgets

It's possible to use an hidden widget for a given field by setting the ui:widget uiSchema directive to hidden for this field:

const schema = { type: "object", properties: { foo: {type: "boolean"} } }; const uiSchema = { foo: {"ui:widget": "hidden"} };


  • Hiding widgets is only supported for boolean, string, number and integer schema types;
  • An hidden widget takes its value from the formData prop.
File widgets

This library supports a limited form of input[type=file] widgets, in the sense that it will propagate file contents to form data state as data-urls.

There are two ways to use file widgets:

By declaring a string json schema type along a data-url format:

const schema = { type: "string", format: "data-url", };

By specifying a ui:widget field uiSchema directive as file:

const schema = { type: "string", }; const uiSchema = { "ui:widget": "file", };
Multiple files

Multiple files selectors are supported by defining an array of strings having data-url as a format:

const schema = { type: "array", items: { type: "string", format: "data-url", } };

Note that storing large dataURIs into form state might slow rendering.

File widget input ref

The included FileWidget exposes a reference to the <input type="file" /> element node as an inputRef component property.

This allows you to programmatically trigger the browser's file selector which can be used in a custom file widget.

Object fields ordering

Since the order of object properties in Javascript and JSON is not guaranteed, the uiSchema object spec allows you to define the order in which properties are rendered using the ui:order property:

const schema = { type: "object", properties: { foo: {type: "string"}, bar: {type: "string"} } }; const uiSchema = { "ui:order": ["bar", "foo"] }; render(( <Form schema={schema} uiSchema={uiSchema} /> ), document.getElementById("app"));

If a guarenteed fixed order is only important for some fields, you can insert a wildcard "*" item in your ui:order definition. All fields that are not referenced explicitly anywhere in the list will be rendered at that point:

const uiSchema = { "ui:order": ["bar", "*"] };

Array item options

orderable option

Array items are orderable by default, and react-jsonschema-form renders move up/down buttons alongside them. The uiSchema object spec allows you to disable ordering:

const schema = { type: "array", items: { type: "string" } }; const uiSchema = { "ui:options": { orderable: false } };
addable option

If either items or additionalItems contains a schema object, an add button for new items is shown by default. You can turn this off with the addable option in uiSchema:

const uiSchema = { "ui:options": { addable: false } };
removable option

A remove button is shown by default for an item if items contains a schema object, or the item is an additionalItems instance. You can turn this off with the removable option in uiSchema:

const uiSchema = { "ui:options": { removable: false } };

Custom CSS class names

The uiSchema object accepts a classNames property for each field of the schema:

const uiSchema = { title: { classNames: "task-title foo-bar" } };

Will result in:

<div class="field field-string task-title foo-bar" > <label> <span>Title*</span> <input value="My task" required="" type="text"> </label> </div>

Custom labels for enum fields

This library supports the enumNames property for enum fields, which allows defining custom labels for each option of an enum:

const schema = { type: "number", enum: [1, 2, 3], enumNames: ["one", "two", "three"] };

This will be rendered using a select box that way:

<select> <option value="1">one</option> <option value="2">two</option> <option value="3">three</option> </select>

Note that string representations of numbers will be cast back and reflected as actual numbers into form state.

Multiple choices list

The default behavior for array fields is a list of text inputs with add/remove buttons. Though there are two alternative simpler widgets for common situations like picking elements against a list of choices; typically this maps to a schema having:

  • an enum list for the items property of an array field
  • with the uniqueItems property set to true


const schema = { type: "array", title: "A multiple choices list", items: { type: "string", enum: ["foo", "bar", "fuzz", "qux"], }, uniqueItems: true };

By default, this will automatically render a multiple select box. If you prefer a list of checkboxes, just set the uiSchema ui:widget directive to "checkboxes" for that field:

const uiSchema = { "ui:widget": "checkboxes" };

Care should be taken when using the required property with arrays. An empty array is sufficient to pass that validation check. If you wish to ensure the user populates the array, you can specify the minimum number of items the user must select with the minItems property.


const schema = { type: "array", minItems: 2, title: "A multiple choices list", items: { type: "string", enum: ["foo", "bar", "fuzz", "qux"], }, uniqueItems: true };

By default, checkboxes are stacked but if you prefer them inline:

const uiSchema = { "ui:widget": "checkboxes", "ui:options": { inline: true } };

See the "Arrays" section of the playground for cool demos.

Autogenerated widget ids

By default, the lib will generate ids unique to the form for all rendered widgets. But if you plan on using multiple instances of the Form component in a same page, it's wise to declare a root prefix for these, using the ui:rootFieldId uiSchema directive:

const uiSchema = { "ui:rootFieldId": "myform" };

So all widgets will have an id prefixed with myform.

Form action buttons

You can provide custom buttons to your form via the Form component's children. A default submit button will be rendered if you don't provide children to the Form component.

render(( <Form schema={schema}> <div> <button type="submit">Submit</button> <button type="button">Cancel</button> </div> </Form> ), document.getElementById("app"));

Warning: there should be a button or an input with type="submit" to trigger the form submission (and then the form validation).

Help texts

Sometimes it's convenient to add some text next to a field to guide the end user filling it; this is the purpose of the ui:help uiSchema directive:

const schema = {type: "string"}; const uiSchema = { "ui:widget": "password", "ui:help": "Hint: Make it strong!" };

Help texts work for any kind of field at any level, and will always be rendered immediately below the field component widget(s), but after contextualized errors, if any.

Auto focus

If you want to focus on a text input or textarea input/on a widget automatically, just set ui:autofocus uiSchema directive to true.

const schema = {type: "string"}; const uiSchema = { "ui:widget": "textarea", "ui:autofocus": true }


Text fields can benefit from placeholders by using the ui:placeholder uiSchema directive:

const schema = {type: "string", format: "uri"}; const uiSchema = { "ui:placeholder": "http://" };

Fields using enum can also use ui:placeholder. The value will be used as the text for the empty option in the select widget.

const schema = {type: "string", enum: ["First", "Second"]}; const uiSchema = { "ui:placeholder": "Choose an option" };

Form attributes

Form component supports the following html attributes:

<Form id="edit-form" className="form form-wide" name="awesomeForm" method="post" target="_blank" action="/users/list" autocomplete="off" enctype="multipart/form-data" acceptcharset="ISO-8859-1" schema={} />

Advanced customization

Field template

To take control over the inner organization of each field (each form row), you can define a field template for your form.

A field template is basically a React stateless component being passed field-related props so you can structure your form row as you like:

function CustomFieldTemplate(props) { const {id, classNames, label, help, required, description, errors, children} = props; return ( <div className={classNames}> <label htmlFor={id}>{label}{required ? "*" : null}</label> {description} {children} {errors} {help} </div> ); } render(( <Form schema={schema} FieldTemplate={CustomFieldTemplate} />, ), document.getElementById("app"));

If you want to handle the rendering of each element yourself, you can use the props rawHelp, rawDescription and rawErrors.

The following props are passed to a custom field template component:

  • id: The id of the field in the hierarchy. You can use it to render a label targetting the wrapped widget.
  • classNames: A string containing the base bootstrap CSS classes merged with any custom ones defined in your uiSchema.
  • label: The computed label for this field, as a string.
  • description: A component instance rendering the field description, if any defined (this will use any custom DescriptionField defined).
  • rawDescription: A string containing any ui:description uiSchema directive defined.
  • children: The field or widget component instance for this field row.
  • errors: A component instance listing any encountered errors for this field.
  • rawErrors: An array of strings listing all generated error messages from encountered errors for this field.
  • help: A component instance rendering any ui:help uiSchema directive defined.
  • rawHelp: A string containing any ui:help uiSchema directive defined. NOTE: rawHelp will be undefined if passed ui:help is a React component instead of a string.
  • hidden: A boolean value stating if the field should be hidden.
  • required: A boolean value stating if the field is required.
  • readonly: A boolean value stating if the field is read-only.
  • displayLabel: A boolean value stating if the label should be rendered or not. This is useful for nested fields in arrays where you don't want to clutter the UI.
  • fields: An array containing all Form's fields including your custom fields and the built-in fields.
  • schema: The schema object for this field.
  • uiSchema: The uiSchema object for this field.
  • formContext: The formContext object that you passed to Form.

Note: you can only define a single field template for a form. If you need many, it's probably time to look at custom fields instead.

Array Field Template

Similarly to the FieldTemplate you can use an ArrayFieldTemplate to customize how your arrays are rendered. This allows you to customize your array, and each element in the array.

function ArrayFieldTemplate(props) { return ( <div> {props.items.map(element => element.children)} {props.canAdd && <button onClick={props.onAddClick}></button>} </div> ); } render(( <Form schema={schema} ArrayFieldTemplate={ArrayFieldTemplate} />, ), document.getElementById("app"));

Please see customArray.js for a better example.

The following props are passed to each ArrayFieldTemplate:

  • DescriptionField: The generated DescriptionField (if you wanted to utilize it)
  • TitleField: The generated TitleField (if you wanted to utilize it).
  • canAdd: A boolean value stating whether new elements can be added to the array.
  • className: The className string.
  • disabled: A boolean value stating if the array is disabled.
  • idSchema: Object
  • items: An array of objects representing the items in the array. Each of the items represent a child with properties described below.
  • onAddClick: (event) => (event) => void: Returns a function that adds a new item to the array.
  • readonly: A boolean value stating if the array is readonly.
  • required: A boolean value stating if the array is required.
  • schema: The schema object for this array.
  • title: A string value containing the title for the array.
  • formContext: The formContext object that you passed to Form.

The following props are part of each element in items:

  • children: The html for the item's content.
  • className: The className string.
  • disabled: A boolean value stating if the array item is disabled.
  • hasMoveDown: A boolean value stating whether the array item can be moved down.
  • hasMoveUp: A boolean value stating whether the array item can be moved up.
  • hasRemove: A boolean value stating whether the array item can be removed.
  • hasToolbar: A boolean value stating whether the array item has a toolbar.
  • index: A number stating the index the array item occurs in items.
  • onDropIndexClick: (index) => (event) => void: Returns a function that removes the item at index.
  • onReorderClick: (index, newIndex) => (event) => void: Returns a function that swaps the items at index with newIndex.
  • readonly: A boolean value stating if the array item is readonly.

Custom widgets and fields

The API allows to specify your own custom widget and field components:

  • A widget represents a HTML tag for the user to enter data, eg. input, select, etc.
  • A field usually wraps one or more widgets and most often handles internal field state; think of a field as a form row, including the labels.

Custom widget components

You can provide your own custom widgets to a uiSchema for the following json data types:

  • string
  • number
  • integer
  • boolean
const schema = { type: "string" }; const uiSchema = { "ui:widget": (props) => { return ( <input type="text" className="custom" value={props.value} required={props.required} onChange={(event) => props.onChange(event.target.value)} /> ); } }; render(( <Form schema={schema} uiSchema={uiSchema} />, ), document.getElementById("app"));

The following props are passed to custom widget components:

  • id: The generated id for this field;
  • schema: The JSONSchema subschema object for this field;
  • value: The current value for this field;
  • required: The required status of this field;
  • disabled: true if the widget is disabled;
  • readonly: true if the widget is read-only;
  • onChange: The value change event handler; call it with the new value everytime it changes;
  • onBlur: The input blur event handler; call it with the the widget id and value;
  • options: A map of options passed as a prop to the component (see Custom widget options).
  • formContext: The formContext object that you passed to Form.

Note: Prior to v0.35.0, the options prop contained the list of options (label and value) for enum fields. Since v0.35.0, it now exposes this list as the enumOptions property within the options object.

Custom component registration

Alternatively, you can register them all at once by passing the widgets prop to the Form component, and reference their identifier from the uiSchema:

const MyCustomWidget = (props) => { return ( <input type="text" className="custom" value={props.value} required={props.required} onChange={(event) => props.onChange(event.target.value)} /> ); }; const widgets = { myCustomWidget: MyCustomWidget }; const uiSchema = { "ui:widget": "myCustomWidget" } render(( <Form schema={schema} uiSchema={uiSchema} widgets={widgets} /> ), document.getElementById("app"));

This is useful if you expose the uiSchema as pure JSON, which can't carry functions.

Note: Until 0.40.0 it was possible to register a widget as object with shape { component: MyCustomWidget, options: {...} }. This undocumented API has been removed. Instead, you can register a custom widget with a React defaultProps property. defaultProps.options can be an object containing your custom options.

Custom widget options

If you need to pass options to your custom widget, you can add a ui:options object containing those properties. If the widget has defaultProps, the options will be merged with the (optional) options object from defaultProps:

const schema = { type: "string" }; function MyCustomWidget(props) { const {options} = props; const {color, backgroundColor} = options; return <input style={{color, backgroundColor}} />; } MyCustomWidget.defaultProps = { options: { color: "red" } }; const uiSchema = { "ui:widget": MyCustomWidget, "ui:options": { backgroundColor: "yellow" } }; // renders red on yellow input render(( <Form schema={schema} uiSchema={uiSchema} /> ), document.getElementById("app"));

Note: This also applies to registered custom components.

Note: Since v0.41.0, the ui:widget object API, where a widget and options were specified with "ui:widget": {component, options} shape, is deprecated. It will be removed in a future release.

Custom field components

You can provide your own field components to a uiSchema for basically any json schema data type, by specifying a ui:field property.

For example, let's create and register a dumb geo component handling a latitude and a longitude:

const schema = { type: "object", required: ["lat", "lon"], properties: { lat: {type: "number"}, lon: {type: "number"} } }; // Define a custom component for handling the root position object class GeoPosition extends React.Component { constructor(props) { super(props); this.state = {...props.formData}; } onChange(name) { return (event) => { this.setState({ [name]: parseFloat(event.target.value) }, () => this.props.onChange(this.state)); }; } render() { const {lat, lon} = this.state; return ( <div> <input type="number" value={lat} onChange={this.onChange("lat")} /> <input type="number" value={lon} onChange={this.onChange("lon")} /> </div> ); } } // Define the custom field component to use for the root object const uiSchema = {"ui:field": "geo"}; // Define the custom field components to register; here our "geo" // custom field component const fields = {geo: GeoPosition}; // Render the form with all the properties we just defined passed // as props render(( <Form schema={schema} uiSchema={uiSchema} fields={fields} /> ), document.getElementById("app"));

Note: Registered fields can be reused across the entire schema.

Field props

A field component will always be passed the following props:

  • schema: The JSON schema for this field;
  • uiSchema: The uiSchema for this field;
  • idSchema: The tree of unique ids for every child field;
  • formData: The data for this field;
  • errorSchema: The tree of errors for this field and its children;
  • registry: A registry object (read next).
  • formContext: A formContext object (read next next).
The registry object

The registry is an object containing the registered custom fields and widgets as well as root schema definitions.

The registry is passed down the component tree, so you can access it from your custom field and SchemaField components.

The formContext object

You can provide a formContext object to the Form, which is passed down to all fields and widgets (including TitleField and DescriptionField). Useful for implementing context aware fields and widgets.

Custom array field buttons

The ArrayField component provides a UI to add, remove and reorder array items, and these buttons use Bootstrap glyphicons. If you don't use glyphicons but still want to provide your own icons or texts for these buttons, you can easily do so using CSS:

i.glyphicon { display: none; } .btn-add::after { content: 'Add'; } .array-item-move-up::after { content: 'Move Up'; } .array-item-move-down::after { content: 'Move Down'; } .array-item-remove::after { content: 'Remove'; } }

Custom SchemaField

Warning: This is a powerful feature as you can override the whole form behavior and easily mess it up. Handle with care.

You can provide your own implementation of the SchemaField base React component for rendering any JSONSchema field type, including objects and arrays. This is useful when you want to augment a given field type with supplementary powers.

To proceed so, pass a fields object having a SchemaField property to your Form component; here's a rather silly example wrapping the standard SchemaField lib component:

import SchemaField from "react-jsonschema-form/lib/components/fields/SchemaField"; const CustomSchemaField = function(props) { return ( <div id="custom"> <p>Yeah, I'm pretty dumb.</p> <SchemaField {...props} /> </div> ); }; const fields = { SchemaField: CustomSchemaField }; render(( <Form schema={schema} uiSchema={uiSchema} formData={formData} fields={fields} /> ), document.getElementById("app"));

If you're curious how this could ever be useful, have a look at the Kinto formbuilder repository to see how it's used to provide editing capabilities to any form field.

Props passed to a custom SchemaField are the same as the ones passed to a custom field.

Customizing the default fields and widgets

You can override any default field and widget, including the internal widgets like the CheckboxWidget that ObjectField renders for boolean values. You can override any field and widget just by providing the customized fields/widgets in the fields and widgets props:

const CustomCheckbox = function(props) { return ( <button id="custom" className={props.value ? "checked" : "unchecked"} onClick={props.onChange(!props.value)}> {props.value} </button> ); }; const widgets = { CheckboxWidget: CustomCheckbox }; render(( <Form schema={schema} uiSchema={uiSchema} formData={formData} widgets={widgets} /> ), document.getElementById("app"));

This allows you to create a reusable customized form class with your custom fields and widgets:

const customFields = {StringField: CustomString}; const customWidgets = {CheckboxWidget: CustomCheckbox}; function MyForm(props) { return <Form fields={customFields} widgets={customWidgets} {...props} />; } render(( <MyForm schema={schema} uiSchema={uiSchema} formData={formData} /> ), document.getElementById("app"));

Custom titles

You can provide your own implementation of the TitleField base React component for rendering any title. This is useful when you want to augment how titles are handled.

Simply pass a fields object having a TitleField property to your Form component:

const CustomTitleField = ({title, required}) => { const legend = required ? title + '*' : title; return <div id="custom">{legend}</div>; }; const fields = { TitleField: CustomTitleField }; render(( <Form schema={schema} uiSchema={uiSchema} formData={formData} fields={fields} /> ), document.getElementById("app"));

Custom descriptions

You can provide your own implementation of the DescriptionField base React component for rendering any description.

Simply pass a fields object having a DescriptionField property to your Form component:

const CustomDescriptionField = ({id, description}) => { return <div id={id}>{description}</div>; }; const fields = { DescriptionField: CustomDescriptionField }; render(( <Form schema={schema} uiSchema={uiSchema} formData={formData} fields={fields} /> ), document.getElementById("app"));

Form data validation

Live validation

By default, form data are only validated when the form is submitted or when a new formData prop is passed to the Form component.

You can enable live form data validation by passing a liveValidate prop to the Form component, and set it to true. Then, everytime a value changes within the form data tree (eg. the user entering a character in a field), a validation operation is performed, and the validation results are reflected into the form state.

Be warned that this is an expensive strategy, with possibly strong impact on performances.

To disable validation entirely, you can set Form's noValidate prop to true.

HTML5 Validation

By default, required field errors will cause the browser to display its standard HTML5 required attribute error messages and prevent form submission. If you would like to turn this off, you can set Form's noHtml5Validate prop to true, which will set noValidate on the form element.

Custom validation

Form data is always validated against the JSON schema.

But it is possible to define your own custom validation rules. This is especially useful when the validation depends on several interdependent fields.

function validate(formData, errors) { if (formData.pass1 !== formData.pass2) { errors.pass2.addError("Passwords don't match"); } return errors; } const schema = { type: "object", properties: { pass1: {type: "string", minLength: 3}, pass2: {type: "string", minLength: 3}, } }; render(( <Form schema={schema} validate={validate} /> ), document.getElementById("app"));


  • The validate() function must always return the errors object received as second argument.
  • The validate() function is called after the JSON schema validation.

Custom error messages

Validation error messages are provided by the JSON Schema validation by default. If you need to change these messages or make any other modifications to the errors from the JSON Schema validation, you can define a transform function that receives the list of JSON Schema errors and returns a new list.

function transformErrors(errors) { return errors.map(error => { if (error.name === "pattern") { error.message = "Only digits are allowed" } return error; }); } const schema = { type: "object", properties: { onlyNumbersString: {type: "string", pattern: "\d*"}, } }; render(( <Form schema={schema} transformErrors={transformErrors} /> ), document.getElementById("app"));


  • The transformErrors() function must return the list of errors. Modifying the list in place without returning it will result in an error.

Error List Display

To disable rendering of the error list at the top of the form, you can set the showErrorList prop to false. Doing so will still validate the form, but only the inline display will show.

render(( <Form schema={schema} showErrorList={false}/> ), document.getElementById("app"));

The case of empty strings

When a text input is empty, the field in form data is set to undefined. String fields that use enum and a select widget work similarly and will have an empty option at the top of the options list that when selected will result in the field being undefined.

One consequence of this is that if you have an empty string in your enum array, selecting that option in the select input will cause the field to be set to undefined, not an empty string.

Styling your forms

This library renders form fields and widgets leveraging the Bootstrap semantics. That means your forms will be beautiful by default if you're loading its stylesheet in your page.

You're not necessarily forced to use Bootstrap; while it uses its semantics, it also provides a bunch of other class names so you can bring new styles or override default ones quite easily in your own personalized stylesheet. That's just HTML after all :)

If you're okay with using styles from the Bootstrap ecosystem though, then the good news is that you have access to many themes for it, which are compatible with our generated forms!

Here are some examples from the playground, using some of the Bootswatch free themes:

Last, if you really really want to override the semantics generated by the lib, you can always create and use your own custom widget, field and/or schema field components.

Schema definitions and references

This library partially supports inline schema definition dereferencing, which is Barbarian for avoiding to copy and paste commonly used field schemas:

{ "definitions": { "address": { "type": "object", "properties": { "street_address": { "type": "string" }, "city": { "type": "string" }, "state": { "type": "string" } }, "required": ["street_address", "city", "state"] } }, "type": "object", "properties": { "billing_address": { "$ref": "#/definitions/address" }, "shipping_address": { "$ref": "#/definitions/address" } } }

(Sample schema courtesy of the Space Telescope Science Institute)

Note that it only supports local definition referencing, we do not plan on fetching foreign schemas over HTTP anytime soon. Basically, you can only reference a definition from the very schema object defining it.

JSON Schema supporting status

This component follows JSON Schema specs. Due to the limitation of form widgets, there are some exceptions as follows:

  • additionalItems keyword for arrays This keyword works when items is an array. additionalItems: true is not supported because there's no widget to represent an item of any type. In this case it will be treated as no additional items allowed. additionalItems being a valid schema is supported.


Development server

$ npm start

A live development server showcasing components with hot reload enabled is available at localhost:8080.

If you want the development server to listen on another host or port, you can use the RJSF_DEV_SERVER env variable:

$ RJSF_DEV_SERVER= npm start


$ npm test
$ npm run tdd


Apache 2



Last updated on 01 Mar 2022

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