Forms in Tina are the main building blocks of your CMS. You will use Forms to:

• Arrange the editing interface for your content
• Expose your content to mutation through user edits
• Process and persist the changes to your content

The recommended way to create forms with Tina is to use the form hooks. These are explained in detail later on in this document, but let's start with a high-level overview of how form hooks are used.

When using form hooks, they should be called inside a Page component; that is, the component that takes your content and renders a page from it. In the following contrived example, we have a Page component that receives its content in the component's props, including a title and some markdownContent:

import * as React from React
import ReactMarkdown from 'react-markdown'

export function Page(props) {
  return (
    <main>
        <h1>{props.title}</h1>
        <ReactMarkdown source={props.markdownContent}>
    </main>
  )
}

Here's how we might call useForm to create a form that will be used to edit this content:

import * as React from React
import ReactMarkdown from 'react-markdown'
import { useForm, usePlugin } from 'tinacms'

export function Page(props) {
  // 1. Create the form
  const [modifiedValues, form] = useForm(formConfig) // formConfig object omitted for brevity; we'll get to this later

  // 2. Register it with the CMS
  usePlugin(form)

  return (
    <main>
      <h1>{modifiedValues.title}</h1>
      <ReactMarkdown source={modifiedValues.markdownContent}>
    </main>
  )
}

useForm returns an object containing all of the form's values that will change as the content is updated in the form. By switching out our original props in the rendering code for this new object, our page will re-render as the content is changed, giving us a real-time preview of the content!

Creating Forms

The useForm hook let's you create a form, but it does not register it with the CMS.

Here is how that hook works:

const [modifiedValues, form, loadingState] = useForm(formConfig, watchedVars)

Hook Return Values

Like other React hooks, the form hooks enclose their return data in an array, expecting developers to assign these values via destructuring.

The first piece of data returned (modifiedValues in the above example) is an object containing all the data that is made editable by the form. As users edit data in the form, the values in this object change.

The second piece of data (form in the above example) is an form object that the hook created.

The third return value is a boolean to denote loading state of the form.

Form Configuration

The first argument that useForm receives (formConfig in the above example) is the object used to configure the form. Forms in Tina are built upon the Final Form library, and inherit all of Final Form's configuration options.

You can see the all of Final Form's form config options in the Form Config Documentation, but the following options will most commonly be used when creating a form:

In addition to Final Form's options, Tina's form hooks accept the following additional configuration options:

interface FormOptions<S> {
  id: any
  label: string
  fields: Field[]
  loadInitialValues?: () => Promise<S>
  onSubmit?: () => Promise<any>
  reset?(): void
  onChange?(state): void
  actions?: any[]
  buttons?: {
    save: string
    reset: string
  }
  __type?: string
}

Now that we know how to configure a form, let's revisit the simplified example from the beginning of this document to demonstrate how we might configure this form:

import * as React from React
import ReactMarkdown from 'react-markdown'
import { useForm, usePlugin } from 'tinacms'

export function Page(props) {
  const formConfig = {
    id: props.fileRelativePath,
    label: 'Edit Post',
    fields: [
      {
        name: 'title',
        label: 'Title',
        component: 'text',
      },
      {
        name: 'markdownContent',
        label: 'content',
        component: 'markdown',
      }
    ],
    initialValues: {
      title: props.title,
      markdownContent: props.markdownContent
    },
    onSubmit: async (formData) => {
      // save the new form data
    },
  }
  const [modifiedValues, form] = useForm(formConfig)

  usePlugin(form)

  return (
    <main>
      <h1>{modifiedValues.title}</h1>
      <ReactMarkdown source={modifiedValues.markdownContent}>
    </main>
  )
}

Note that when using these basic hooks, you are expected to implement the save functionality yourself by adding an onSubmit function. By default, Tina makes no assumptions about how your content is stored. These basic form hooks are building blocks for creating more purpose-built tools to fit specific use cases.

Watched Vars: Preserve Form Reactivity

The second argument that can be passed to the form hooks is an optional object containing values that the form will need to react to. Use this when dealing with data from external sources or in an environment with Hot Module Replacement; in other words, when you expect this data to change and it's essential to keep the form in sync with it.

interface WatchableFormValue {
  values: object
  label: string
  fields: Field[]
}

Registering Forms

In order to use a form you must register it with the CMS. There are two main approaches to register forms in Tina: page forms and screen plugins.

Example 1: Page Forms

For general page forms, use the usePlugin hook.

Tip: At one point these were known as Local Forms

src/templates/blog-post.js

import { usePlugin } from 'tinacms'
import { useJsonForm } from 'next-tinacms-json'

function BlogPostTemplate(props) {
  // Create the form
  const [data, form] = useJsonForm(props.data.dataJson)

  // Register it with the CMS
  usePlugin(form)

  return <h1>{data.firstName}</h1>
}

Example 2: Forms as Screens

Screens are additional UI modals accessible from the CMS menu. Reference the useFormScreenPlugin hook to see an example of registering a form as a screen.

Form Helpers

The three hooks described thus far are the basic interface for creating forms, and they aim to support a broad set of use cases. For specific use cases, we've created some simplified interfaces for quickly setting up forms depending on the backend. Take a look at the integration packages for Next.js to learn more.

Customizing Form Buttons

Note: The 'Save' and 'Reset' button text can also be configured on the sidebar or toolbar when defining the CMS options. If buttons are configured on the CMS through the sidebar or toolbar options, those values will take precedent over button values passed to a form. It is now recommended to configure button text on the form intead of the CMS.

'Save' & 'Reset' buttons accompany all forms. They may render at the bottom of the sidebar, in a modal, or on the toolbar. When clicked, these buttons should generally invoke the onSubmit(For 'Save') & reset(For 'Reset') functions associated with the form.

There may be times when you want to change the button text to improve UX or provide a better description of the action for an editor. For example, you may want the 'Save' button to say 'Commit' and the 'Reset' button to say 'Discard Changes'.

Below is an example of a form options object with these custom button options passed in:

const [author, authorForm] = useJsonForm(data.dataJson, {
  label: 'Author',
  fields: [
    {
      name: 'author',
      label: 'Author',
      component: 'select',
      options: [
        'Herbert Huncke',
        'Allen Ginsberg',
        'Jack Kerouac',
        'William S. Burroughs',
      ],
    },
  ],
  buttons: {
    save: 'Commit',
    reset: 'Discard Changes',
  },
})

Reuse with a composition

When using the same button configuraiton for every form, it can be repetitive to continually define the button options. You can use a composition for this. Below is an example if you created a cms directory with a useForm composition to add the custom button values on every form.

src/cms/use-form.ts

import {
  useForm as baseUseForm,
  FormOptions,
  WatchableFormValues,
} from 'tinacms'
export const useForm = (options: FormOptions, watch?: WatchableFormValues) =>
  baseUseForm(
    {
      buttons: {
        save: 'Save Changes',
        reset: 'Reset Form',
      },
      ...options,
    },
    watch
  )

This is how that useForm composition could be used, setting up a baseline configuration for the general useForm hook from Tina.

src/pages/index.js

import { useForm } from '../cms/use-form'

export default function Home(props) {
  const formOptions = {
    //...
  }
  useForm(formOptions)
}

The formOptions defined in this example would be the config object referenced above.

Handling Loading State

There are times when you may need to fetch form data asynchronously via loadInitialValues. When this function is called, the form's loading state is set to true until the promise resolves with the returned data.

The loading state can be used to conditionally render a 'loading' component until the form data is available to render.

import {useForm, usePlugin} from 'tinacms'

export default function Page() {
  const [data, form, loading] = useForm({
    id: props.fileRelativePath,
    label: 'Edit Post',
    fields: [
      {
        name: 'title',
        label: 'Title',
        component: 'text',
      },
      {
        name: 'date',
        label: 'Date',
        component: 'date',
      }
    ],
    loadInitialValues() {
      return fetch(exampleRequest).then(res => res.json())
    },
    onSubmit(formData) => {
      // post saved form data
    },
  })

  return (
    {loading} ?<h1>Loading...</h1>: (
    <section>
      <h1>{data.title}</h1>
      <div>{data.date}</div>
    </section>
    )
  )
}

Inline Forms

Refer to the Inline Editing docs.

Last Edited: September 10, 2020