查询订单待分账金额 
商户可通过调用此接口查询订单剩余待分金额。 官方文档
js
wxpay.v2.pay.profitsharingorderamountquery.post({
  mch_id,
  transaction_id,
  nonce_str,
  sign_type,
})
.then(
  ({ 
    data: {
      return_code,
      return_msg,
      mch_id,
      transaction_id,
      unsplit_amount,
      nonce_str,
      sign,
    },
  }) => ({
    return_code,
    return_msg,
    mch_id,
    transaction_id,
    unsplit_amount,
    nonce_str,
    sign,
  })
)