如何使用node.js从json引用键

Question

我如何访问以下json数据

"users":{
    "2211392761":{"username":"user1"},
    "14300995184":{"username":"user2"},
    "2781554712":{"username":"user3"},
    "3554341":{"username":"user4"},
    "202611":{"username":"user5"},
    "17754300653761":{"username":"user6"}
}

到目前为止我有这个，我知道这是完全错误的：

Object.keys(jsonevents["events"]).forEach(function(key) {
    if(eventName == jsonevents["events"][key]["name"]){
        if(jsonevents["events"][key]["users"]){
            if(jsonevents['events'][key]["users"][message.author.id]){
                delete jsonevents['events'][key]["users"][message.author.id];
                fs.writeFile(eventsjson, JSON.stringify(jsonevents),'utf8');
                sayMessage += "```User is no longer part of the event "+jsonevents['events'][key]["name"]+"```";
            } else {
                sayMessage += "```user is not in the event "+jsonevents['events'][key]["name"]+"```";
            }
        } else {
            sayMessage += "```Why do we have no users```";
        }
    } else {
        //sayMessage += "```No event found```";
    }
});

我需要通过传递用户名来访问密钥，因此user2会给我14300995184因此我可以使用它来从事件中删除用户。

Answer 1

您可以使用find()搜索Object.entries并返回正确的对象。 它将返回一个key/value数组，键将是您所追求的：

 let users = { "2211392761":{"username":"user1"}, "14300995184":{"username":"user2"}, "2781554712":{"username":"user3"}, "3554341":{"username":"user4"}, "202611":{"username":"user5"}, "17754300653761":{"username":"user6"} } let found = Object.entries(users).find(([key, value]) => value.username === "user2") console.log(found && found[0]) // found is undefined if not found 

Answer 2

您可以迭代users对象的entries （键值对），并使用.find查找与您要查找的用户名匹配的用户名。 条目中的第一项（密钥）将是您要查找的内容：

 const obj = { "users": { "2211392761": { "username": "user1" }, "14300995184": { "username": "user2" }, "2781554712": { "username": "user3" }, "3554341": { "username": "user4" }, "202611": { "username": "user5" }, "17754300653761": { "username": "user6" } } } const findEntry = usernameToFind => { const foundEntry = Object.entries(obj.users) .find(([, { username }]) => username === usernameToFind); if (foundEntry) return foundEntry[0]; }; console.log(findEntry('user5')); console.log(findEntry('userthatdoesntexist'));