老师你好，

1. forwardRef

Antd 源码第 319 行 (https://github.com/ant-design/ant-design/blob/master/components/button/button.tsx)：
最后导出 Button 组件时，为什么用到

const Button = React.forwardRef<unknown, ButtonProps>(InternalButton) as CompoundedComponent

而不是直接 export default InternalButton 呢

2. iconNode

第 277 行 (https://github.com/ant-design/ant-design/blob/master/components/button/button.tsx)

const iconNode =
    icon && !innerLoading ? (
      icon
    ) : (
      <LoadingIcon existIcon={!!icon} prefixCls={prefixCls} loading={!!innerLoading} />
    );
    
<button
      {...(rest as NativeButtonProps)}
      type={htmlType}
      className={classes}
      onClick={handleClick}
      disabled={mergedDisabled}
      ref={buttonRef}
>
      {iconNode}
      {kids}
</button>    

这里为什么没有像下面这样。在JSX里直接写，而是要用 iconNode 包起来呢？

 <button
      {...(rest as NativeButtonProps)}
      type={htmlType}
      className={classes}
      onClick={handleClick}
      disabled={mergedDisabled}
      ref={buttonRef}
    >
      {
	      icon && !innerLoading
	      ? (icon)
	      : (<LoadingIcon existIcon={!!icon} prefixCls={prefixCls} loading={!!innerLoading} />);
      }
      {kids}
    </button>