Why does `mapProps` remove `children`? about recompose HOT 2 CLOSED

const mapPropsWithChildren = R.partial(
  R.pipe(R.pipe(R.converge, R.unapply)(R.merge), mapProps),
  [R.pick(['children'])],
)

import * as React from "react";
import { mapProps } from "recompose";
import * as R from "ramda";

const Box = (props: any) => <div {...props} />;

const Alert = mapProps(
  R.applySpec({
    style: {
      backgroundColor: R.ifElse(
        R.propEq("type", "danger"),
        R.always("red"),
        R.always("blue")
      ),
      height: R.always("200px"),
      margin: R.always("20px")
    },
    children: R.prop("children")
  })
)(Box);

const NonFunctionalAlert = ({ type, children }: any) => (
  <div
    style={{
      backgroundColor: type === "danger" ? "red" : "blue",
      margin: "20px",
      height: "200px"
    }}
  >
    {children}
  </div>
);

export default () => (
  <div>
    <Alert type={"danger"}>Danger</Alert>
    <NonFunctionalAlert type={"info"}>Info</NonFunctionalAlert>
  </div>
);