metamask-extension/ui/components/component-library/form-text-field/README.mdx

import { Story, Canvas, ArgsTable } from '@storybook/addon-docs';

import { TextField, TextFieldBase } from '../';
import { FormTextField } from './form-text-field';

# FormTextField

The `FormTextField` is an input component to create forms. It bundles the [TextField](/docs/components-componentlibrary-textfield--default-story), [Label](/docs/components-componentlibrary-label--default-story) and [HelpText](/docs/components-componentlibrary-helptext--default-story) components together.

<Canvas>
  <Story id="components-componentlibrary-formtextfield--default-story" />
</Canvas>

## Props

The `FormTextField` accepts all props below as well as all [Box](/docs/components-ui-box--default-story#props) component props

<ArgsTable of={FormTextField} />

`FormTextField` accepts all [TextField](/docs/components-componentlibrary-textfield--default-story#props)
component props

<ArgsTable of={TextField} />

`FormTextField` accepts all [TextFieldBase](/docs/components-componentlibrary-textfield--default-story#props)
component props

<ArgsTable of={TextFieldBase} />

### Id

Use the `id` prop to set the `id` of the `FormTextField` component. This is required for accessibility when the `label` prop is set. It is also used internally to link the `label` and `input` elements using `htmlFor`, so clicking on the `label` will focus the `input`.

<Canvas>
  <Story id="components-componentlibrary-formtextfield--id" />
</Canvas>

```jsx
import { FormTextField } from '../../component-library';

<FormTextField
  id="accessible-input-id"
  label="If label prop exists id prop is required for accessibility"
/>;
```

### Label

Use the `label` prop to add a label to the `FormTextField` component. Uses the [Label](/docs/components-componentlibrary-label--default-story) component. Use the `labelProps` prop to pass props to the `Label` component. To use a custom label component see the [Custom Label or HelpText](#custom-label-or-helptext) story example.

<Canvas>
  <Story id="components-componentlibrary-formtextfield--label-story" />
</Canvas>

```jsx
import { FormTextField } from '../../component-library';

<FormTextField id="input-with-label" label="Label content appears here" />;
```

### HelpText

Use the `helpText` prop to add help text to the `FormTextField` component. Uses the [HelpText](/docs/components-componentlibrary-helptext--default-story) component. Use the `helpTextProps` prop to pass props to the `HelpText` component. To use a custom help text component see the [Custom Label or HelpText](#custom-helpText-or-helptext) story example. When `error` is true the `helpText` will be rendered as an error message.

<Canvas>
  <Story id="components-componentlibrary-formtextfield--help-text-story" />
</Canvas>

```jsx
import { FormTextField } from '../../component-library';

<FormTextField helpText="HelpText content appears here" />;
<FormTextField
  error
  helpText="When error is true the help text will be rendered as an error message"
/>;
```

### Form Example

An example of a form using the `FormTextField` component.

<Canvas>
  <Story id="components-componentlibrary-formtextfield--form-example" />
</Canvas>

```jsx
import React, { useState, useEffect } from 'react';
import {
  DISPLAY,
  COLORS,
  ALIGN_ITEMS,
  TEXT,
} from '../../../helpers/constants/design-system';

import Box from '../../ui/box/box';

import {
  ButtonPrimary,
  ButtonSecondary,
  FormTextField,
  ICON_NAMES,
  Text,
} from '../../component-library';

const FORM_STATE = {
  DEFAULT: 'default',
  SUCCESS: 'success',
  ERROR: 'error',
};

const VALIDATED_VALUES = {
  NETWORK_NAME: 'network name',
  NEW_RPC_URL: 'new rpc url',
  CHAIN_ID: 'chain id',
};

const ERROR_MESSAGES = {
  NETWORK_NAME: `Please enter "${VALIDATED_VALUES.NETWORK_NAME}"`,
  NEW_RPC_URL: `Please enter "${VALIDATED_VALUES.NEW_RPC_URL}"`,
  CHAIN_ID: `Please enter "${VALIDATED_VALUES.CHAIN_ID}"`,
};

const [submitted, setSubmitted] = useState(FORM_STATE.DEFAULT);

const [values, setValues] = useState({
  networkName: '',
  newRpcUrl: '',
  chainId: '',
});

const [errors, setErrors] = useState({
  networkName: '',
  newRpcUrl: '',
  chainId: '',
});

useEffect(() => {
  setErrors({
    networkName:
      values.networkName &&
      values.networkName.toLowerCase() !== VALIDATED_VALUES.NETWORK_NAME
        ? ERROR_MESSAGES.NETWORK_NAME
        : '',
    newRpcUrl:
      values.newRpcUrl &&
      values.newRpcUrl.toLowerCase() !== VALIDATED_VALUES.NEW_RPC_URL
        ? ERROR_MESSAGES.NEW_RPC_URL
        : '',
    chainId:
      values.chainId &&
      values.chainId.toLowerCase() !== VALIDATED_VALUES.CHAIN_ID
        ? ERROR_MESSAGES.CHAIN_ID
        : '',
  });
}, [values]);

const handleClearForm = () => {
  setValues({ networkName: '', newRpcUrl: '', chainId: '' });
  setErrors({ networkName: '', newRpcUrl: '', chainId: '' });
  setSubmitted(FORM_STATE.DEFAULT);
};

const handleOnChange = (e) => {
  if (submitted === FORM_STATE.ERROR) {
    setErrors({ networkName: '', newRpcUrl: '', chainId: '' });
    setSubmitted(FORM_STATE.DEFAULT);
  }
  setValues({
    ...values,
    [e.target.name]: e.target.value,
  });
};

const handleOnSubmit = (e) => {
  e.preventDefault();
  if (errors.networkName || errors.newRpcUrl || errors.chainId) {
    setSubmitted(FORM_STATE.ERROR);
  } else {
    setSubmitted(FORM_STATE.SUCCESS);
  }
};

return (
  <>
    <Box
      as="form"
      onSubmit={handleOnSubmit}
      marginBottom={4}
      style={{ width: '100%', maxWidth: '420px' }}
    >
      <FormTextField
        marginBottom={4}
        label="Network name"
        placeholder="Enter 'network name'"
        required
        name="networkName"
        id="networkName"
        onChange={handleOnChange}
        value={values.networkName}
        error={Boolean(submitted === FORM_STATE.ERROR && errors.networkName)}
        helpText={submitted === FORM_STATE.ERROR ? errors.networkName : null}
      />
      <FormTextField
        marginBottom={4}
        label="New RPC URL"
        placeholder="Enter 'new RPC URL'"
        required
        name="newRpcUrl"
        id="newRpcUrl"
        onChange={handleOnChange}
        value={values.newRpcUrl}
        error={Boolean(submitted === FORM_STATE.ERROR && errors.newRpcUrl)}
        helpText={submitted === FORM_STATE.ERROR ? errors.newRpcUrl : null}
      />
      <FormTextField
        label="Chain ID"
        marginBottom={4}
        placeholder="Enter 'chain ID'"
        required
        name="chainId"
        id="chainId"
        onChange={handleOnChange}
        value={values.chainId}
        error={Boolean(submitted === FORM_STATE.ERROR && errors.chainId)}
        helpText={submitted === FORM_STATE.ERROR ? errors.chainId : null}
      />
      <Box display={DISPLAY.FLEX} alignItems={ALIGN_ITEMS.CENTER} gap={1}>
        <ButtonPrimary type="submit">Submit</ButtonPrimary>
      </Box>
    </Box>
    <ButtonSecondary icon={ICON_NAMES.CLOSE} onClick={handleClearForm} danger>
      Clear form
    </ButtonSecondary>
    {submitted === FORM_STATE.SUCCESS && (
      <Text variant={TEXT.BODY_LG} color={COLORS.SUCCESS_DEFAULT} marginTop={4}>
        Form successfully submitted!
      </Text>
    )}
  </>
);
```

### Custom Label or HelpText

There will be times when you will want to use a custom `Label` or `HelpText`. This can be done by simply not providing `label` or `helpText` props to the `FormTextField` component. You can then use the `Label` and `HelpText` components to create your own custom label or help text.

<Canvas>
  <Story id="components-componentlibrary-formtextfield--custom-label-or-help-text" />
</Canvas>

```jsx
import {
  SIZES,
  DISPLAY,
  COLORS,
  ALIGN_ITEMS,
  JUSTIFY_CONTENT,
} from '../../../helpers/constants/design-system';

import Box from '../../ui/box/box';

import {
  ButtonLink,
  FormTextField,
  HelpText,
  ICON_NAMES,
  Icon,
  Label,
  TEXT_FIELD_TYPES,
  Text,
} from '../../component-library';

<Text marginBottom={4}>
  Examples of how one might customize the Label or HelpText within the
  FormTextField component
</Text>
<Box
  display={DISPLAY.FLEX}
  justifyContent={JUSTIFY_CONTENT.SPACE_BETWEEN}
  alignItems={ALIGN_ITEMS.FLEX_END}
>
  <Box display={DISPLAY.FLEX} alignItems={ALIGN_ITEMS.CENTER}>
    {/**
      * If you need a custom label
      * or require adding some form of customization
      * import the Label component separately
      */}
    <Label htmlFor="custom-spending-cap" required>
      Custom spending cap
    </Label>
    <Icon
      name={ICON_NAMES.INFO}
      size={SIZES.SM}
      marginLeft={1}
      color={COLORS.ICON_ALTERNATIVE}
    />
  </Box>
  <ButtonLink size={SIZES.AUTO}>Use default</ButtonLink>
</Box>
<FormTextField
  id="custom-spending-cap"
  placeholder="Enter a number"
  rightAccessory={<ButtonLink size={SIZES.AUTO}>Max</ButtonLink>}
  marginBottom={4}
  type={TEXT_FIELD_TYPES.NUMBER}
/>
<FormTextField
  label="Swap from"
  placeholder="0"
  type={TEXT_FIELD_TYPES.NUMBER}
/>
<Box
  display={DISPLAY.FLEX}
  alignItems={ALIGN_ITEMS.FLEX_START}
  justifyContent={JUSTIFY_CONTENT.SPACE_BETWEEN}
>
  {/**
    * If you need a custom help text
    * or require adding some form of customization
    * import the HelpText component separately and handle the error
    * logic yourself
    */}
  <HelpText htmlFor="chainId" required paddingRight={2} marginTop={1}>
    Only enter a number that you're comfortable with the contract accessing
    now or in the future. You can always increase the token limit later.
  </HelpText>
  <ButtonLink size={SIZES.AUTO} marginLeft="auto" marginTop={1}>
    Max
  </ButtonLink>
</Box>
```