使用许多嵌套的 forEach 处理对象的更好方法？

Question

我想知道在处理具有嵌套 arrays 属性的对象时是否有更好的方法来处理嵌套的 forEach。

我的 object（总结）：

{
 ...,
 "tx_responses": [
   {
     ...
     "logs" : [
       {
         ...,
         "events": [
             {
                 "type": "coin_received",
                 "attributes": [
                     {
                         "key": "receiver",
                         "value": "somesome"
                     },
                     {
                         "key": "amount",
                         "value": "somesome"
                     }
                 ]
             },
             ...
             {
                 "type": "transfer",
                 "attributes": [
                     {
                         "key": "recipient",
                         "value": "somesome"
                     },
                     {
                         "key": "sender",
                         "value": "somesome"
                     },
                     {
                         "key": "amount",
                         "value": "somesome"
                     }
                 ]
             },
             {
                 "type": "withdraw_rewards",
                 "attributes": [
                     {
                         "key": "amount",
                         "value": "somesomesomehere"
                     },
                     {
                         "key": "validator",
                         "value": "somesome"
                     }
                 ]
             },
             ...
         ]
     }
 ],
...

我实际上是在尝试提取"type": "withdraw_rewards"的"attributes"数组中的所有{ key: 'amount', value: 'somesomesomehere' }对象： "events"数组中的“withdraw_rewards”object。

目前这是我为执行任务而编写的代码：

getWithdrawnAmounts: async(del_addr_) => {
    let withdrawnAmounts = [];
    const res = await axios.get("some_url_that_uses_del_addr_");
    res.data.tx_responses.forEach(txr => {
        txr.logs.forEach(log => {
            log.events.forEach(evnt => {
                if (evnt.type == "withdraw_rewards") {
                    evnt.attributes.forEach(attr => {
                        if (attr.key == "amount") {
                            withdrawnAmounts.push(attr);
                        }
                    })
                }
            })
        })
    });
    return withdrawnAmounts;
}

该代码帮助我获得我需要的东西，但我想知道是否有更好的方法来编写我的代码，这样我就不必使用这么多嵌套.forEach方法。 我想知道是否应该使用.flat()或.flatMap()但我很想知道人们将如何处理这个问题？

谢谢！

Answer 1

您将不得不为要深入的每个级别调用某种迭代。

现在，有一种更实用的方法来获取所需的数据，使用flatMap和filter ：

 const data = { "tx_responses": [{ "logs": [{ "events": [{ "type": "coin_received", "attributes": [{ "key": "receiver", "value": "somesome" }, { "key": "amount", "value": "somesome" }]}, { "type": "transfer", "attributes": [{ "key": "recipient", "value": "somesome" }, { "key": "sender", "value": "somesome" }, { "key": "amount", "value": "somesome" }]}, { "type": "withdraw_rewards", "attributes": [{ "key": "amount", "value": "somesomesomehere" }, { "key": "validator", "value": "somesome" }]}]}]}]}; const result = data.tx_responses.flatMap(r => r.logs.flatMap(l => l.events.filter(e => e.type === 'withdraw_rewards').flatMap(e => e.attributes.filter(a => a.key === 'amount')) ) ); console.log(result);