ant-design/components/form/FormItem.tsx

import React from 'react';
import PropTypes from 'prop-types';
import classNames from 'classnames';
import PureRenderMixin from 'rc-util/lib/PureRenderMixin';
import Row from '../row';
import Col from '../col';
import { WrappedFormUtils } from './Form';
import { FIELD_META_PROP } from './constants';
import warning from '../_util/warning';

export interface FormItemLabelColOption {
  span: number;
  offset?: number;
}

export interface FormItemProps {
  prefixCls?: string;
  id?: string;
  label?: React.ReactNode;
  labelCol?: FormItemLabelColOption;
  wrapperCol?: FormItemLabelColOption;
  help?: React.ReactNode;
  extra?: React.ReactNode;
  validateStatus?: 'success' | 'warning' | 'error' | 'validating';
  hasFeedback?: boolean;
  className?: string;
  required?: boolean;
  style?: React.CSSProperties;
  colon?: boolean;
}

export interface FormItemContext {
  form: WrappedFormUtils;
  vertical: boolean;
}

export default class FormItem extends React.Component<FormItemProps, any> {
  static defaultProps = {
    hasFeedback: false,
    prefixCls: 'ant-form',
    colon: true,
  };

  static propTypes = {
    prefixCls: PropTypes.string,
    label: PropTypes.oneOfType([PropTypes.string, PropTypes.node]),
    labelCol: PropTypes.object,
    help: PropTypes.oneOfType([PropTypes.node, PropTypes.bool]),
    validateStatus: PropTypes.oneOf(['', 'success', 'warning', 'error', 'validating']),
    hasFeedback: PropTypes.bool,
    wrapperCol: PropTypes.object,
    className: PropTypes.string,
    id: PropTypes.string,
    children: PropTypes.node,
    colon: PropTypes.bool,
  };

  static contextTypes = {
    form: PropTypes.object,
    vertical: PropTypes.bool,
  };

  context: FormItemContext;

  componentDidMount() {
    warning(
      this.getControls(this.props.children, true).length <= 1,
      '`Form.Item` cannot generate `validateStatus` and `help` automatically, ' +
      'while there are more than one `getFieldDecorator` in it.',
    );
  }

  shouldComponentUpdate(...args) {
    return PureRenderMixin.shouldComponentUpdate.apply(this, args);
  }

  getHelpMsg() {
    const context = this.context;
    const props = this.props;
    if (props.help === undefined && context.form) {
      return this.getId() ? (context.form.getFieldError(this.getId()) || []).join(', ') : '';
    }

    return props.help;
  }

  getControls(children, recursively: boolean) {
    let controls: React.ReactElement<any>[] = [];
    const childrenArray = React.Children.toArray(children);
    for (let i = 0; i < childrenArray.length; i++) {
      if (!recursively && controls.length > 0) {
        break;
      }

      const child = childrenArray[i] as React.ReactElement<any>;
      if (child.type as any === FormItem) {
        continue;
      }
      if (!child.props) {
        continue;
      }
      if (FIELD_META_PROP in child.props) {
        controls.push(child);
      } else if (child.props.children) {
        controls = controls.concat(this.getControls(child.props.children, recursively));
      }
    }
    return controls;
  }

  getOnlyControl() {
    const child = this.getControls(this.props.children, false)[0];
    return child !== undefined ? child : null;
  }

  getChildProp(prop) {