antd-mobile/2x/es/utils/traverse-react-node.js

<div align="center">

import React from 'react';
import { isFragment } from 'react-is';
export function traverseReactNode(children, fn) {
  let i = 0;
  function handle(target) {
    React.Children.forEach(target, child => {
      if (!isFragment(child)) {
        fn(child, i);
        i += 1;
      } else {
        handle(child.props.children);
      }
    });
  }
  handle(children);
}