Javascript array object compare to get unlisted array result

August 20, 2023

I have 2 arrays object below:

var data: The complete data
var choose: The only choose

var data = [
    {
        "day": "Mon",
        "id": "SC0001",
        "deviceID": "DA0002",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "day": "Wed",
        "id": "SC0001",
        "deviceID": "DA0002",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "day": "Fri",
        "id": "SC0001",
        "deviceID": "DA0002",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "day": "Sat",
        "id": "SC0001",
        "deviceID": "DA0002",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "day": "Sun",
        "id": "SC0001",
        "deviceID": "DA0002",
        "time": "08:00",
        "trigger": "ON"
    }
];

var choose = [
    {
        "deviceID": "DA0002",
        "id": "SC0001",
        "day": "Mon",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "deviceID": "DA0002",
        "id": "SC0001",
        "day": "Wed",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "deviceID": "DA0002",
        "id": "SC0001",
        "day": "Sat",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "deviceID": "DA0002",
        "id": "SC0001",
        "day": "Sun",
        "time": "08:00",
        "trigger": "ON"
    }
];

for(var i=0; i<data.length; i++) {
        var day = data[i].day;
        var scheduleID = data[i].id;
        var deviceID = data[i].deviceID;
        
        console.log(day);
        
    //How to get Friday array here?
}

As We can see above if compare with both array object, I need to get the unlisted result.
So how can I get the array object for Friday only?

>Solution :

Use Array::filter() to filter your data array and use Array::some() in the filter callback to check that the current item’s day doesn’t exist in the choose array.

It works if day is unique per an object in an array, otherwise you should compare several unique fields.

const result = data.filter(item => !choose.some(item2 => item.day === item2.day));
console.log(result);

<script>
var data = [
    {
        "day": "Mon",
        "id": "SC0001",
        "deviceID": "DA0002",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "day": "Wed",
        "id": "SC0001",
        "deviceID": "DA0002",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "day": "Fri",
        "id": "SC0001",
        "deviceID": "DA0002",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "day": "Sat",
        "id": "SC0001",
        "deviceID": "DA0002",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "day": "Sun",
        "id": "SC0001",
        "deviceID": "DA0002",
        "time": "08:00",
        "trigger": "ON"
    }
];

var choose = [
    {
        "deviceID": "DA0002",
        "id": "SC0001",
        "day": "Mon",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "deviceID": "DA0002",
        "id": "SC0001",
        "day": "Wed",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "deviceID": "DA0002",
        "id": "SC0001",
        "day": "Sat",
        "time": "08:00",
        "trigger": "ON"
    },
    {
        "deviceID": "DA0002",
        "id": "SC0001",
        "day": "Sun",
        "time": "08:00",
        "trigger": "ON"
    }
];
</script>