如何在firebase中使用带有或条件的两个where子句

Question

我是Firebase的新手，请帮助我解决此问题

    getChats(callback){ db.collection('chat') .onSnapshot(snapshot=>{
        (snapshot.docChanges()).forEach(data=>{
            if(data.type=='added'){
                callback(data.doc.data());
            }
        }) }) }

响应：

{body: "send me your user_name", from: "admin1", time: so, to: "keshav"}
{body: "admin i forget my password can ", from: "keshav", time: so, to: "admin"}
{body: "hii", "from ": "admin", time: so, to: "keshav"}
{body: "Hello admin how are you ", "from ": "keshav", time: so, to: "admin"}

现在我想获取同时满足两个条件的数据 条件：-

  

其中（from = admin和to = keshav）或（from = keshav和to = admin）