如何在javascript中向相同的对象键添加相同的id值

Question

i have a problem with adding new values to existing objects when they have equal values. My point is to add new value to existing object, but when object value is equal with other postion object value then they have to get same new value, but otherwise object get just a value.

var array = [
    {"first": [10, 20], "last": [40, 50]},
    {"first": [60, 22], "last": [10, 20]},
    {"first": [40, 50], "last": [60, 22]},
    {"first": [40, 50], "last": [44, 33]}
];

for (var i = 0; i < (array.length); i++) {
    for (var j = 0; j < (array.length); j++) {
        if (array[i].first[0] == array[j].last[0] && array[i].first[1] == array[j].last[1]) {
            /* I'm not sure, what to do here
               but I want to add same values to equal objects
            */
            array[i].first.push(i);
            array[j].first.push(i);
        }
    }
}

I want to get that output:

var array = [
    {"first": [10, 20, 1], "last": [40, 50, 2]},
    {"first": [60, 22, 3], "last": [10, 20, 1]},
    {"first": [40, 50, 2], "last": [60, 22, 3]},
    {"first": [40, 50, 2], "last": [44, 33, 4]}
];

last number are new values,but im not sure how do get that output, i think maybe one way is to save equal objects positions and then doing something with them , but im not sure, maybe can somebody give me advice?

Answer 1

As in comments to Your question, I also find this problem quite strange. But... I think this is what You seek:

    <script>
        var array = [
            {"first": [10, 20], "last": [40, 50]},
            {"first": [60, 22], "last": [10, 20]},
            {"first": [40, 50], "last": [60, 22]},
            {"first": [40, 50], "last": [44, 33]}
        ];
        // This variable will hold unique subarrays. 
        // Index of it will be the number added to each subarray.
        var matches = new Array();
        var check_it = function(matches,subarr)
        {
            // Finding index of subarray in matches
            var index = matches.map( /./.test, RegExp( "^"+subarr+"$"  )).indexOf(true); 
            // If this subarray is new
            if(index === -1)
            { 
               // Add copy of it to matches
               matches.push([subarr[0],subarr[1]]);
               // Assing index to it
               subarr.push(matches.length-1);
            }
            // If this subarray exist in matches
            else
            {
                // Add the index of first match to it
                subarr.push(index);
            }
        }
        for (var i = 0; i < (array.length); i++) {
            // For each subarray do the checking.
            check_it(matches,array[i].first);
            check_it(matches,array[i].last);
        }
        console.log(array);
    </script>

From here I get code to find index of array in array .