Check for duplicates in JSON

Question

I have a json object:

var object1 = [
                {"value1": "1", "value2": "2", "value3": "3",},
                {"value1": "1", "value2": "5", "value3": "7",},
                {"value1": "6", "value2": "9", "value3": "5",},
                {"value1": "6", "value2": "9", "value3": "5",}
]

Now I want to

take each record out of that object
and check how many times exact copy of that record is appearing in that object?

If it is only 1 copy do something and if it is more than 2 do something else. There are few answers on JSON duplicates but they target specific value not full record.

So I will take the record:

{ "value1": "1", "value2": "2", "value3": "3",}

and compare it against object1. The above record will return 1 as there is only 1 copy inside object1

For Future use. Given these records

var asset = [
    { value1: "1", value2: "2", value3: "3" },
    { value1: "1", value2: "5", value3: "7" },
    { value1: "6", value2: "9", value3: "5" },
    { value1: "6", value2: "9", value3: "5" }
];

This code can be used to find duplicates:


function countEqual(oo, pp) {
    var count = 0;
    oo.forEach(function (el) {
        var i, equal = true;
        for (i in el) {
            equal = equal && el[i] === pp[i];
        }
        equal && count++;
    });
    return count;
}

var cleaned = [];

asset.forEach(function (itm) {
    var unique = true;
    cleaned.forEach(function (itm2) {
        if (_.isEqual(itm, itm2)) unique = false;
    });
    if (unique) cleaned.push(itm);
});

for (var i = 0; i < cleaned.length; i++) {
    if (countEqual(asset, cleaned[i]) === 1) {
        // DO SOMETHING
    }
    else {
        // DO SOMETHING ELSE
    }
}

1) That's not JSON. 2) you can't have duplicate keys in JavaScript objects. The end result of your assignment is that each object in `object1` will have one `value2` key. — Andrew Whitaker, Jun 22 '15 at 14:14
possible duplicate of [Remove duplicates from an array of objects in javascript](http://stackoverflow.com/questions/2218999/remove-duplicates-from-an-array-of-objects-in-javascript) — Patrick Evans, Jun 22 '15 at 14:18
value1 compares to value 1? and 2 to 2 and 3 to 3? How should look the result? — Nina Scholz, Jun 22 '15 at 14:20

Thomas Eschemann · Answer 1 · 2015-06-22T15:07:13.600

If what you are looking for is a function that will count the number of occurrences of an object in an array, the following code should help you (this assumes that the properties in your objects will always follow the same order. If you aren't sure about that you should use a proper equality check function):

var nbOcc = function (needle, haystack) {
  return haystack.filter(function (record) {
    return JSON.stringify(needle) === JSON.stringify(record);
  }).length;
};

console.log(nbOcc({
  "value1": "1",
  "value2": "2",
  "value3": "3",
}, object1)); // 1

console.log(nbOcc({
  "value1": "6",
  "value2": "9",
  "value3": "5",
}, object1)); // 2

JSFiddle link

Nina Scholz · Accepted Answer · 2015-06-22T14:56:56.010

var asset = [
    { value1: "1", value2: "2", value3: "3" },
    { value1: "1", value2: "5", value3: "7" },
    { value1: "6", value2: "9", value3: "5" },
    { value1: "6", value2: "9", value3: "5" }
];

function countEqual(oo, pp) {
    var count = 0;
    oo.forEach(function (el) {
        var i, equal = true;
        for (i in el) {
            equal = equal && el[i] === pp[i];
        }
        equal && count++;
    });
    return count;
}
console.log(countEqual(asset, { value1: "1", value2: "1", value3: "2" })); // 0
console.log(countEqual(asset, { value1: "1", value2: "2", value3: "3" })); // 1
console.log(countEqual(asset, { value1: "6", value2: "9", value3: "5" })); // 2

Yes that worked fine. From my side I had to clean up "asset" object to contain only unique values. Then, use for loop on the new unique array and apply it to your code. Thank you! — Danielok1993, Jun 22 '15 at 15:08

Check for duplicates in JSON

2 Answers2