javascript Lodash：是否可以将地图与异步功能一起使用？
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Lodash: is it possible to use map with async functions?
提问by realtebo
Consider this code
考虑这个代码
const response = await fetch('<my url>');
const responseJson = await response.json();
responseJson = _.sortBy(responseJson, "number");
responseJson[0] = await addEnabledProperty(responseJson[0]);
What addEnabledPropertydoes is to extend the object adding an enabledproperty, but this is not important. The function itself works well
什么addEnabledProperty是扩展对象添加enabled属性，但这并不重要。该功能本身运行良好
async function addEnabledProperty (channel){
const channelId = channel.id;
const stored_status = await AsyncStorage.getItem(`ChannelIsEnabled:${channelId}`);
let boolean_status = false;
if (stored_status == null) {
boolean_status = true;
} else {
boolean_status = (stored_status == 'true');
}
return _.extend({}, channel, { enabled: boolean_status });
}
Is there a way to use _.map(or another system), to loop trough entire responseJson array to use addEnabledPropertyagainst each element?
有没有办法使用_.map（或其他系统）来循环遍历整个 responseJson 数组以addEnabledProperty针对每个元素使用？
I tried:
我试过：
responseJson = _.map(responseJson, function(channel) {
return addEnabledProperty(channell);
});
But it's not using async so it freeze the app.
但它没有使用异步所以它冻结了应用程序。
I tried:
我试过：
responseJson = _.map(responseJson, function(channel) {
return await addEnabledProperty(chanell);
});
But i got a js error (about the row return await addEnabledProperty(chanell);)
但我有一个 js 错误（关于行return await addEnabledProperty(chanell);）
await is a reserved word
await 是一个保留字
Then tried
然后试过
responseJson = _.map(responseJson, async function(channel) {
return await addEnabledProperty(channell);
});
But I got an array of Promises... and I don't understand why...
但是我得到了一系列 Promises ......我不明白为什么......
What else!??
还有什么！？？
EDIT: I understand your complains about I didn't specify that addEnabledProperty()returns a Promise, but, really, I didn't know it. In fact, I wrote "I got an array of Promises... and I don't understand why"
编辑：我理解你抱怨我没有指定addEnabledProperty()返回 a Promise，但是，真的，我不知道。事实上，我写了“我得到了一系列的承诺......但我不明白为什么”
回答by dhilt
To process your response jsons in parallel you may use Promise.all:
要并行处理您的响应 json，您可以使用Promise.all：
const responseJson = await response.json();
responseJson = _.sortBy(responseJson, "number");
let result = await Promise.all(_.map(responseJson, async (json) =>
await addEnabledProperty(json))
);
Since addEnabledPropertymethod is async, the following also should work (per @CRice):
由于addEnabledProperty方法是异步的，以下也应该有效（根据@CRice）：
let result = await Promise.all(_.map(responseJson, addEnabledProperty));
回答by Rodrigo Leite
You can use Promise.all()to run all the promises in your array.
您可以使用Promise.all()来运行数组中的所有承诺。
responseJson = await Promise.all(_.map(responseJson, (channel) => {
return addEnabledProperty(channel);
}));
回答by Javid Jamae
I found that I didn't have to put the async / await inside of the Promise.allwrapper.
我发现我不必将 async / await 放在Promise.all包装器中。
Using that knowledge, in conjunction with lodash chain (_.chain) could result in the following simplified version of the accepted answer:
使用这些知识，结合 lodash chain ( _.chain) 可能会产生以下已接受答案的简化版本：
const responseJson = await Promise.all( _
.chain( response.json() )
.sortBy( 'number' )
.map( json => addEnabledProperty( json ) )
.value()
)
回答by Juneho Nam
How about using partial.js(https://github.com/marpple/partial.js)
如何使用 partial.js( https://github.com/marpple/partial.js)
It cover both promise and normal pattern by same code.
它通过相同的代码涵盖了 promise 和 normal 模式。
_p.map([1, 2, 3], async (v) => await promiseFunction());
