Search in a nested array and return a value from that array?

Question

I have an API endpoint that returns a JSON response with a bunch of game ids. That response looks like this (and yes, it is heavily snipped).

{
"finished": [
        {
        "game_id": 8
        },
        {
        "game_id": 9
        },
        {
        "game_id": 11
        }
    ],
"unfinished": [
        {
        "game_id": 12
        },
        {
        "game_id": 13
        }
    ]
}

What I want to achieve probably needs a bunch separate functions. But I want to search the array for a specific ID, that is user inputed. And depending if it is in the "finished" or "unfinished", return the value from that key.

Lets say that I want to search the array for ID of 13. That ID would be found in "unfinished". And if that is the case, I want to return the first ID in the "unfinished" array, ID 12.

If I would search the array for ID 9, that would be found in "finished", then return that ID (9).

If I would search the array for ID 12, that would be found in "unfinished", return the first ID from unfinished, ID 12.

Hope this makes sense.

I have been making some test just with searching the array, but no luck at all

const test = _.findKey(game_ids, function(o) { return o.game_id == 8; });

So, if finished, return id, if unfinished return id of 1st item in unfinished array. What happens if nothing is found? — Ori Drori
– Ori Drori, Commented Oct 10, 2017 at 20:03
Exactly! And if nothing is found, maybe return the first ID of unfinished again. Haven't thought about that situation =) — Adam
– Adam, Commented Oct 10, 2017 at 20:09

Ori Drori · Accepted Answer · 2017-10-10 20:13:21Z

1

Use _.find() with a short circuit to try the unfinished if the game id is not found in finished, and if nothing found return the 1st of finished:

const data = {"finished":[{"game_id":8},{"game_id":9},{"game_id":11}],"unfinished":[{"game_id":12},{"game_id":13}]};

const findId = (game_id) => _.find(data.finished, { game_id }) || (_.find(data.unfinished, { game_id }) && data.unfinished[0]) || data.unfinished[0];

console.log(findId(13));

console.log(findId(9));

console.log(findId(200));

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>

answered Oct 10, 2017 at 20:13

Ori Drori

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Comments

Sua Morales · Accepted Answer · 2017-10-10 20:10:58Z

1

So at a basic level you need to iterate through two arrays to find some value.

You mentioned lodash which has a great find utility function. With this function in hand, you would call this function twice, once for each array. Make sure to handle the case where no game is found.

ex:

var targetVal = userInput; 
game_id = _.find(apiResponse. finished, { game_id: targetVal })

answered Oct 10, 2017 at 20:10

Sua Morales

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janos · Accepted Answer · 2017-10-10 20:22:42Z

1

Here's a pure JavaScript solution:

var response = {"finished":[{"game_id":8},{"game_id":9},{"game_id":11}],"unfinished":[{"game_id":12},{"game_id":13}]};

function find(response, value) {
    var i;
    for (i = 0; i < response.finished.length; i++) {
        if (response.finished[i].game_id === value) {
            return value;
        }
    }

    for (i = 0; i < response.unfinished.length; i++) {
        if (response.unfinished[i].game_id === value) {
            return response.unfinished[0].game_id;
        }
    }

    return undefined;
}

edited Oct 10, 2017 at 20:22

answered Oct 10, 2017 at 20:10

janos

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1 Comment

Adam Over a year ago

Thanks! Very helpful and educational! And it works to =)

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