@material-ui/core/es/FormHelperText/FormHelperText.js

React components that implement Google's Material Design.

import _extends from "@babel/runtime/helpers/extends";
import _objectWithoutProperties from "@babel/runtime/helpers/objectWithoutProperties";
import React from 'react';
import PropTypes from 'prop-types';
import classNames from 'classnames';
import withStyles from '../styles/withStyles';
import { formControlState } from '../InputBase/InputBase';
export const styles = theme => ({
  /* Styles applied to the root element. */
  root: {
    color: theme.palette.text.secondary,
    fontFamily: theme.typography.fontFamily,
    fontSize: theme.typography.pxToRem(12),
    textAlign: 'left',
    marginTop: 8,
    lineHeight: '1em',
    minHeight: '1em',
    margin: 0,
    '&$error': {
      color: theme.palette.error.main
    },
    '&$disabled': {
      color: theme.palette.text.disabled
    }
  },

  /* Styles applied to the root element if `error={true}`. */
  error: {},

  /* Styles applied to the root element if `disabled={true}`. */
  disabled: {},

  /* Styles applied to the root element if `margin="dense"`. */
  marginDense: {
    marginTop: 4
  },

  /* Styles applied to the root element if `variant="filled"` or `variant="outlined"`. */
  contained: {
    margin: '8px 12px 0'
  },

  /* Styles applied to the root element if `focused={true}`. */
  focused: {},

  /* Styles applied to the root element if `filled={true}`. */
  filled: {},

  /* Styles applied to the root element if `required={true}`. */
  required: {}
});

function FormHelperText(props, context) {
  const {
    classes,
    className: classNameProp,
    component: Component,
    disabled,
    error,
    filled,
    focused,
    margin,
    required,
    variant
  } = props,
        other = _objectWithoutProperties(props, ["classes", "className", "component", "disabled", "error", "filled", "focused", "margin", "required", "variant"]);

  const fcs = formControlState({
    props,
    context,
    states: ['variant', 'margin', 'disabled', 'error', 'filled', 'focused', 'required']
  });
  return React.createElement(Component, _extends({
    className: classNames(classes.root, {
      [classes.contained]: fcs.variant === 'filled' || fcs.variant === 'outlined',
      [classes.marginDense]: fcs.margin === 'dense',
      [classes.disabled]: fcs.disabled,
      [classes.error]: fcs.error,
      [classes.filled]: fcs.filled,
      [classes.focused]: fcs.focused,
      [classes.required]: fcs.required
    }, classNameProp)
  }, other));
}

FormHelperText.propTypes = process.env.NODE_ENV !== "production" ? {
  /**
   * The content of the component.
   */
  children: PropTypes.node,

  /**
   * Override or extend the styles applied to the component.
   * See [CSS API](#css-api) below for more details.
   */
  classes: PropTypes.object.isRequired,

  /**
   * @ignore
   */
  className: PropTypes.string,

  /**
   * The component used for the root node.
   * Either a string to use a DOM element or a component.
   */
  component: PropTypes.oneOfType([PropTypes.string, PropTypes.func, PropTypes.object]),

  /**
   * If `true`, the helper text should be displayed in a disabled state.
   */
  disabled: PropTypes.bool,

  /**
   * If `true`, helper text should be displayed in an error state.
   */
  error: PropTypes.bool,

  /**
   * If `true`, the helper text should use filled classes key.
   */
  filled: PropTypes.bool,

  /**
   * If `true`, the helper text should use focused classes key.
   */
  focused: PropTypes.bool,

  /**
   * If `dense`, will adjust vertical spacing. This is normally obtained via context from
   * FormControl.
   */
  margin: PropTypes.oneOf(['dense']),

  /**
   * If `true`, the helper text should use required classes key.
   */
  required: PropTypes.bool,

  /**
   * The variant to use.
   */
  variant: PropTypes.oneOf(['standard', 'outlined', 'filled'])
} : {};
FormHelperText.defaultProps = {
  component: 'p'
};
FormHelperText.contextTypes = {
  muiFormControl: PropTypes.object
};
export default withStyles(styles, {
  name: 'MuiFormHelperText'
})(FormHelperText);