查找数组中的值满足条件的数组索引

Question

The client is receiving a message from socket.io on the server. The data of this message has this object:

{
    from,
    text,
    dateTimeSent,
    chatId
}

These refer to data about a chat message that is being sent from another user on the system.

On the client-side the user is storing information about all of the chats they are participants of. This data comes from a MongoDB that has a collection called chats , in which, each chat has an _id.

So basically, the client-side is storing information all information about each chat they have access to, including the _id of the chat.

How would i use chatId received on the socket, then search for that ID in the array that stores the _id of the chat that this message should go into?

Is there a JavaScript function where you can search for the value of a specific field in an array?

The following is the array that the user is storing on their client. How would i search for the value of chatId in this array?

[

    [
        "0",
        {
            "_id":"5ccb37c82eab402834818e8f",
            "participants":[
                {
                    "_id":"5ccb37c82eab402834818e91",
                    "userEmail":"test2@gmail.com"
                },
                {
                    "_id":"5ccb37c82eab402834818e90",
                    "userEmail":"test@gmail.com"
                }
            ],
            "chatType":"chat",
            "messages":[
                {
                    "dateTimeSent":"2019-05-02T19:50:19.000Z",
                    "_id":"5ccb49fba2129f160cb22ac8",
                    "text":"",
                    "from":"test2@gmail.com"
                },
                {
                    "dateTimeSent":"2019-05-02T19:50:58.896Z",
                    "_id":"5ccb4a27a2129f160cb22ade",
                    "text":"dfdf",
                    "from":"test2@gmail.com"
                },
                {
                    "dateTimeSent":"2019-05-02T19:51:03.093Z",
                    "_id":"5ccb4a27a2129f160cb22add",
                    "text":"",
                    "from":"test2@gmail.com"
                },
                {
                    "dateTimeSent":"2019-05-02T19:54:13.070Z",
                    "_id":"5ccb4aeaa2129f160cb22b06",
                    "text":"",
                    "from":"test2@gmail.com"
                },
                {
                    "dateTimeSent":"2019-05-02T21:45:29.498Z",
                    "_id":"5ccb64fbf769fd273c500889",
                    "text":"hi",
                    "from":"test@gmail.com"
                },
                {
                    "dateTimeSent":"2019-05-02T21:45:31.020Z",
                    "_id":"5ccb64fbf769fd273c500888",
                    "text":"hi",
                    "from":"test@gmail.com"
                }
            ],
            "__v":0
        }
    ],
    [
        "1",
        {
            "_id":"5ccb5197a2129f160cb22b13",
            "participants":[
                {
                    "_id":"5ccb5197a2129f160cb22b15",
                    "userEmail":"test2@gmail.com"
                },
                {
                    "_id":"5ccb5197a2129f160cb22b14",
                    "userEmail":"adam2.cole@northumbria.ac.uk"
                }
            ],
            "chatType":"chat",
            "messages":[
                {
                    "dateTimeSent":"2019-05-02T20:22:50.633Z",
                    "_id":"5ccb519ca2129f160cb22b1b",
                    "text":"fgfhgfbvb",
                    "from":"test2@gmail.com"
                },
                {
                    "dateTimeSent":"2019-05-02T20:22:51.924Z",
                    "_id":"5ccb519ca2129f160cb22b1a",
                    "text":"fgfhgfbvb",
                    "from":"test2@gmail.com"
                },
                {
                    "dateTimeSent":"2019-05-02T20:22:52.751Z",
                    "_id":"5ccb519ca2129f160cb22b19",
                    "text":"fgfhgfbvb",
                    "from":"test2@gmail.com"
                }
            ],
            "__v":0
        }
    ]

]

Answer 1

Find index of array where value in array meets condition

You're probably looking for array.findIndex() . Give it an array, and a function that runs for each item. Return true when it comes across the ID you're looking for.