Javascript Search Array for Object with a certain Value

Question

i have an array of objects, looking like this:

[
    {
        "label": "anystring",
        "processowner": ["any name"],
        "withwhat": ["any text"],
        "withwho": ["any text"],
        "processstep": ["any text"],
        "cluster": ["anyValue1"]
    },
    {
        "label": "anystring",
        "processowner": ["any name"],
        "withwhat": ["any text"],
        "withwho": ["any text"],
        "processstep": ["any text"],
        "cluster": ["anyValue2"]
    },
    {
        "label": "anystring",
        "processowner": ["any name"],
        "withwhat": ["any text"],
        "withwho": ["any text"],
        "processstep": ["any text"],
        "cluster": ["anyValue1"]
    },
.........
]

The important Key, Value pair is "cluster". It is possible that there are more objects with the same '"cluster"'-Value. What i want is a new Array with just the "cluster"-Value. But each only once! That's were im struggling.

What i did so far is looping over the given array and compare the current "cluster"-Value with a second(final) array "tempNewJson" (second loop) - filled with the first object "initObj" of the given array in it. If the Value is already in "tempNewJson" i want the code to do nothing. If the Value is not yet in "tempNewJson" i want to add it. But i still get duplicates and a wrong number of Values in my final array "tempNewJson".

function convertJSON(initJson) {
var initObj = {};
initObj.title = initJson[0].cluster.toString();
initObj.scale = 6;
initObj.type = 'group-case-5-3';
initObj.children = [];
tempNewJson.push(initObj);
var contains = false;
// Schleife über alle Items in initialem JSON
for (var i = 0; i < initJson.length; i++) {
    // Schleife über bisher hinzugefügte Objekte in tempNewJSON
    contains = false;
     for(var j = 0; j < tempNewJson.length; j++) {
         contains = false;
         if(initJson[i].cluster.toString() === tempNewJson[j].title) {
             contains = true;
             console.log(initJson[i].cluster.toString());
             break;
         }
     }
     if(contains === false) {
            initObj.title = initJson[i].cluster.toString();
            console.log('test: ' + initJson[i].cluster.toString());
            tempNewJson.push(initObj);
     }
 }
}

Anyone knows how to fix this? Thanks.

The Output should look like this

["anyValue1", "anyValue2", .....]

I used Nina Scholz's answer like this:

var result = initJson.reduce(function (tempNewJson, initJson) {
    !~tempNewJson.indexOf(initJson.cluster) && tempNewJson.push(initJson.cluster.toString());
    return tempNewJson;
}, []);
 console.log(result);

What i get know ist the following array:

['anyValue1', 'anyValue2', 'anyValue1', 'anyValue3', 'anyValue1', .........

]

But what i want is:

['anyValue1', 'anyValue2', 'anyValue3', 'anyValue4', 'anyValue5', .........

]

I'm unclear on what the output should be; can you provide a sample? — Explosion Pills
– Explosion Pills, Commented Nov 2, 2015 at 16:02
if you use it !~tempNewJson.indexOf(initJson.cluster) && tempNewJson.push(initJson.cluster.toString()) this way, then you need a toString() also in the indexOf part like !~tempNewJson.indexOf(initJson.cluster.toString()) && tempNewJson.push(initJson.cluster.toString()) — Nina Scholz
– Nina Scholz, Commented Nov 2, 2015 at 16:55

Explosion Pills · Accepted Answer · 2015-11-02 16:11:43Z

1

If you can support it I would use a Set.

let set = new Set;
initObj.map(item =>
    item.cluster.map(cluster => set.add(cluster))
);

Now set is an iterable with unique cluster values.

Otherwise you can do this with an array, but you have to do the unicity check on your own:

let newArr = [];
initObj.map(item =>
    item.cluser.map(cluster => {
        if (-1 === newArr.indexOf(cluster)) {
            newArr.push(cluster);
        }
    });
);

answered Nov 2, 2015 at 16:11

Explosion Pills

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Comments

Nina Scholz · Accepted Answer · 2015-11-02 16:24:16Z

0

Simple solution with Array.prototype.reduce. The advantage of this method is the possibillity to return something (here an array) and take it as an input for the next iteration.

var array = [{
        "label": "anystring",
        "cluster": "anyValue1"
    }, {
        "label": "anystring",
        "cluster": "anyValue2"
    }, {
        "label": "anystring",
        "cluster": "anyValue1"
    }],
    result = array.reduce(function (r, a) {
        !~r.indexOf(a.cluster) && r.push(a.cluster);
        return r;
    }, []);
document.write('<pre>' + JSON.stringify(result, 0, 4) + '</pre>');

answered Nov 2, 2015 at 16:24

Nina Scholz

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3 Comments

dnks23 Over a year ago

This is short and works, but i still have duplicates in the result array.

Nina Scholz Over a year ago

@dnks23, please supply some more data.

dnks23 Over a year ago

tried to update my post above, does this help? dont know what else to provide.... @Nina Scholz

Joel Almeida · Accepted Answer · 2015-11-02 16:10:37Z

You can use map() and filter() for this.

var data = [
    {
        "label": "anystring",
        "processowner": ["any name"],
        "withwhat": ["any text"],
        "withwho": ["any text"],
        "processstep": ["any text"],
        "cluster": ["anyValue1"]
    },
    {
        "label": "anystring",
        "processowner": ["any name"],
        "withwhat": ["any text"],
        "withwho": ["any text"],
        "processstep": ["any text"],
        "cluster": ["anyValue2"]
    },
    {
        "label": "anystring",
        "processowner": ["any name"],
        "withwhat": ["any text"],
        "withwho": ["any text"],
        "processstep": ["any text"],
        "cluster": ["anyValue1"]
    }
];

var clusters = data.map(function(item) {
    return item.cluster[0];
});

clusters = clusters.filter(function(item, pos) {
    return clusters.indexOf(item) == pos;
})

console.log(clusters)

somethinghere · Accepted Answer · 2015-11-02 16:17:36Z

You can use pure JS to simply loop through your array and create a result object that contains all the objects with certain cluster keys, which creates a very useful object! The same thing is true for just getting your desired array of cluster names.

// Simplified test object without all the value
var test = [
  {"id": 1,"cluster": ["anyValue1"]},
  {"id": 2,"cluster": ["anyValue2"]},
  {"id": 3,"cluster": ["anyValue1"]}
];

var result = {};
for(var i = 0; i < test.length; i++){
  for(var c = 0; c < test[i].cluster.length; c++){
    result[test[i].cluster[c]] = result[test[i].cluster[c]] || [];
    result[test[i].cluster[c]].push(test[i]);
  }
}

document.write('<pre>');
document.write(JSON.stringify(result));

var result = [];
for(var i = 0; i < test.length; i++){
  for(var c = 0; c < test[i].cluster.length; c++){
    if(result.indexOf(test[i].cluster[c]) < 0)
      result.push(test[i].cluster[c])
  }
}

document.write('<br /><br />' + JSON.stringify(result));
document.write('</pre>');

Both objects could be very useful in their own way.

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