New array of objects by comparing and pushing unique objects

Question

I have 2 arrays of objects exclude and people, I want to create a new object by checking exclude properties against people properties and only adding objects in people that don't feature in exclude. So far my attempt is a little wild and wondering if someone can help make things a little better or offer a nicer solution?

Fiddle http://jsfiddle.net/kyllle/k02jw2j0/

JS

var exclude = [{
    id: 1,
    name: 'John'
}];

var peopleArr = [{
    id: 1,
    name: 'John'
}, {
    id: 2,
    name: 'James'
}, {
    id: 3,
    name: 'Simon'
}];

var myObj = [];
for (key in peopleArr) {
    for (k in exclude) {

        if (JSON.stringify(peopleArr[key]) != JSON.stringify(exclude[k])) {

            console.log(peopleArr[key]);
            myObj.push(peopleArr[key]);

        }
    }
}

console.log(myObj);

davidkonrad · Accepted Answer · 2015-11-05 10:43:49Z

1

Under the assumption that exclude can have multiple items, I would use a combination of filter() and forEach() :

var newArray = peopleArr.filter(function(person) {
    include = true;
    exclude.forEach(function(exl) {
        if (JSON.stringify(exl) == JSON.stringify(person)) {
            include = false;
            return;
        }
    })
    if (include) return person;
})

forked fiddle -> http://jsfiddle.net/6c24rte8/

answered Nov 5, 2015 at 10:43

davidkonrad

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Comments

Yeldar Kurmangaliyev · Accepted Answer · 2015-11-05 10:40:26Z

1

You repeat some JSON.stringify calls.
You can convert your arrays to JSON once, and then reuse it. Also, you can replace your push by Array.prototype.filter.

var excludeJson = exclude.map(JSON.stringify);

peopleArr = peopleArr.filter(function(x) { 
    return excludeJson.indexOf(JSON.stringify(x)) === -1;
});

Here is the working snippet:

var exclude = [{
    id: 1,
    name: 'John'
}];

var peopleArr = [{
    id: 1,
    name: 'John'
}, {
    id: 2,
    name: 'James'
}, {
    id: 3,
    name: 'Simon'
}];

var excludeJson = exclude.map(JSON.stringify);

peopleArr = peopleArr.filter(function(x) { 
  return excludeJson.indexOf(JSON.stringify(x)) === -1;
});

document.body.innerText = JSON.stringify(peopleArr);

answered Nov 5, 2015 at 10:40

Yeldar Kurmangaliyev

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Comments

Jamiec · Accepted Answer · 2015-11-05 10:40:35Z

1

This can be achieved with .filter and .findIndex

var myObj = peopleArr.filter(function(person){
   var idx = exclude.findIndex(function(exc) { return person.id == exc.id && person.name == exc.name; });
   return idx == -1; // means current person not found in the exclude list
});

I have explicitly compared the actual properties back to the original, there is nothing particularly wrong with your original way of comparing the stringified version (JSON.stringify(e) == JSON.stringify(x) could be used in my example)

answered Nov 5, 2015 at 10:40

Jamiec

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