remove duplicated objects from javaScript array if meets certain criteria

Question

I have an array with many objects (Drugs). each object has 3 keys: "Drug1", "Drug2", and riskingRate. How can i remove duplicated objects if Drug1 and Drug2 values are same (riskingRate is not important in finding duplicats). then keep object with higher riskingRate and remove others. here is a simple array:

var Warfarin = [{
    "Drug1": "Warfarin",
    "Drug2": "vitamin K",
    "riskRating": "C",
}, {
    "Drug": "aspirin",
    "Drug2": "MiFEPRIStone",
    "riskRating": "C",
}, {
    "Drug1": "Warfarin",
    "Drug2": "Omacetaxine",
    "riskRating": "X",
}, {
    "Drug1": "Warfarin",
    "Drug2": "vitamin K",
    "riskRating": "X",
},{
    "Drug1": "Warfarin",
    "Drug2": "vitamin K",
    "riskRating": "A",
}]

in this example objects 0, 3 and 4 are duplicated and the object 3 has a higher riskingRate. (riskingRate X>D>C>B>A). how can I remove objects 0 and 4 and keep objects 1,2 and 3. Thanks.

Is it intentional that the second element has Drug and not Drug1 as a key name? — arvi1000
– arvi1000, Commented Feb 28, 2018 at 21:33
Possible duplicate of Remove duplicates from an array of objects in JavaScript — Heretic Monkey
– Heretic Monkey, Commented Feb 28, 2018 at 21:33

Titus · Accepted Answer · 2018-02-28 21:29:23Z

3

You can do something like this:

var weights = ["X", "D", "C", "B", "A"];

var Warfarin = [{
    "Drug1": "Warfarin",
    "Drug2": "vitamin K",
    "riskRating": "C",
}, {
    "Drug": "aspirin",
    "Drug2": "MiFEPRIStone",
    "riskRating": "C",
}, {
    "Drug1": "Warfarin",
    "Drug2": "Omacetaxine",
    "riskRating": "X",
}, {
    "Drug1": "Warfarin",
    "Drug2": "vitamin K",
    "riskRating": "X",
},{
    "Drug1": "Warfarin",
    "Drug2": "vitamin K",
    "riskRating": "A",
}];

var response = Warfarin.sort((v1, v2) => (weights.indexOf(v1.riskRating) - weights.indexOf(v2.riskRating)))
.reduce((a, c)=>{
    if(!a.some(v => (v.Drug1 == c.Drug1 && v.Drug2 == c.Drug2))){
        a.push(c);
    }
    return a;
}, []);

console.log(response);

What this does is to first sort the array based on the objects' riskRating so the higher risk objects will be at the start, then just reduce the array and don't include the duplicates in the resulting array.

answered Feb 28, 2018 at 21:29

Titus

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2 Comments

john sadeghi Over a year ago

Hi. thanks for your help. console: ReferenceError: weights is not defined

Titus Over a year ago

@johnsadeghi You're missing the weights variable that I've included at the start of my snippet.

trincot · Accepted Answer · 2018-02-28 21:43:21Z

3

Here is a solution without sorting, but with an ES6 Map, which would make it run in O(n) time instead of O(nlogn):

const Warfarin = [{"Drug1": "Warfarin","Drug2": "vitamin K","riskRating": "C",}, {"Drug": "aspirin","Drug2": "MiFEPRIStone","riskRating": "C",}, {"Drug1": "Warfarin","Drug2": "Omacetaxine","riskRating": "X",},{"Drug1": "Warfarin","Drug2": "vitamin K","riskRating": "X",},{"Drug1": "Warfarin","Drug2": "vitamin K","riskRating": "A",}];

const result = Array.from(Warfarin.reduce ( (acc, obj) => {
    const key = JSON.stringify([obj.Drug1,obj.Drug2]);
    return !acc.has(key) || acc.get(key).riskRating < obj.riskRating
        ? acc.set(key, obj) : acc; 
}, new Map).values());

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

answered Feb 28, 2018 at 21:43

trincot

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2 Comments

arvi1000 Over a year ago

Why JSON.stringify([obj.Drug1,obj.Drug2]) as the key, and not just [obj.Drug1,obj.Drug2], since Maps don't require keys to be strings?

trincot Over a year ago

Because if you pass a new array as key, it will always be considered different (comparison will be by reference).

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