Javascript array check and combine

Question

I have two arrays containing some objects and I need to know how to combine them and exclude any duplicates. (For example, the object that contains apple: 222 from the second array should be excluded, if it already exists in the first array.)

Check below:

var arr1 = [
    {apple: 111, tomato: 55},
    {apple: 222, tomato: 55}
]

var arr2 = [
    {apple: 222, tomato: 55},
    {apple: 333, tomato: 55}
]

I want the result to be like this:

   var res = [
    {apple: 111, tomato: 55},
    {apple: 222, tomato: 55},
    {apple: 333, tomato: 55}
]

How can I do that in javascript?

Not sure why you changed the example code, but I've amended my answer to fit. — Andy
– Andy, Commented Oct 16, 2013 at 13:26

score 1 · Accepted Answer · 2013-10-21 17:09:11Z

1

Does this solution fit with your needs (demo) ?

var res, i, item, prev;

// merges arrays together
res = [].concat(arr1, arr2);

// sorts the resulting array based on the apple property
res.sort(function (a, b) {
    return a.apple - b.apple;
});

for (i = res.length - 1; i >= 0; i--) {
    item = res[i];

    // compares each item with the previous one based on the apple property
    if (prev && item.apple === prev.apple) {

        // removes item if properties match
        res.splice(i, 1);
    }
    prev = item;
}

edited Oct 21, 2013 at 17:09

answered Oct 21, 2013 at 16:37

user1636522

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Comments

Andy · Accepted Answer · 2013-10-16 13:21:24Z

1

You could write a dedupe function.

if (!Array.prototype.dedupe) {
  Array.prototype.dedupe = function (type) {
    for (var i = 0, l = this.length - 1; i < l; i++) {
      if (this[i][type] === this[i + 1][type]) {
        this.splice(i, 1);
        i--; l--;
      }
    }
    return this;
  }
}

function combine(arr1, arr2, key) {
  return arr1
    .concat(arr2)
    .sort(function (a, b) { return a[key] - b[key]; })
    .dedupe(key);   
}

var combined = combine(arr1, arr2, 'apple');

Fiddle.

edited Oct 16, 2013 at 13:21

answered Oct 16, 2013 at 11:24

Andy

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