docs: function insertSpace(child, needInserted) {
      // Check the child if is undefined or null.
      if (child == null) {
          return;
      }
      var SPACE = needInserted ? ' ' : '';
      // strictNullChecks oops.
      if (typeof child !== 'string' && typeof child !== 'number' && isString(child.type) && isTwoCNChar(child.props.children)) {
          return React.cloneElement(child, {}, child.props.children.split('').join(SPACE));
      }
      if (typeof child === 'string') {
          if (isTwoCNChar(child)) {
              child = child.split('').join(SPACE);
          }
          return React.createElement(
              'span',
              null,
              child
          );
      }
      return child;
  }