filtering and adding the object to array without duplicates

Question

Im trying to make sure I dont have this object in the array before adding it. If it is inside I want to remove it and add the new one at the top (very similar to a browser history)

    let numberArray =  [ {
  "name": "Smith",
    "number": "088-002-0002",
},
 {
  "name": "Jhon",
    "number": "088-111-2222",
},];

let test = { "name": "Smith",
  "number": "088-002-0002",};

numberArray.filter(obj => obj.number !== test.number);
numberArray.unshift(test);

console.log(numberArray);

//Expected
 Array [
 Object {
    "name": "Smith",
    "number": "088-002-0002",
 },
 Object {
   "name": "Jhon",
   "number": "088-111-2222",
 },
]

Are you going to use this operation a lot or very few times? — molamk
– molamk, Commented Feb 25, 2019 at 23:36

Ele · Accepted Answer · 2019-02-25 23:26:39Z

1

Use the function findIndex and then check if the indexOf > -1, in that case, remove that index, and finally unshift the new object.

// This is to illustrate -> "name": "Smithhhhh"
let numberArray = [{    "name": "Smithhhhh",    "number": "088-002-0002",  },  {    "name": "Jhon",    "number": "088-111-2222",  }],
    test = {  "name": "Smith",  "number": "088-002-0002",},
    indexOf = numberArray.findIndex(obj => obj.number === test.number);
    
if (indexOf !== -1) numberArray.splice(indexOf, 1);

numberArray.unshift(test);
console.log(numberArray);

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

edited Feb 25, 2019 at 23:26

answered Feb 25, 2019 at 23:16

Ele

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Comments

Jack Bashford · Accepted Answer · 2019-02-25 23:15:32Z

0

You can use includes and indexOf with unshift like so:

function addToArray(obj, arr) {
    if (arr.includes(obj)) {
        arr.splice(arr.indexOf(obj), 1);
        arr.unshift(obj);
    }
}

answered Feb 25, 2019 at 23:15

Jack Bashford

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6 Comments

Ele Over a year ago

indexOf and includes?, this is comparing different references in memory.

Jack Bashford Over a year ago

@Ele what do you mean?

Ele Over a year ago

let obj1 = {name: "Ele"}; let obj2 = {name: "Ele"} -> obj1 === obj2 // returns false

Ele Over a year ago

The function includes compares each object vs the object you're passing as param. So, is comparing references in memory and not the keys, values within it.

Jack Bashford Over a year ago

How should I do it then?

|

ziggy wiggy · Accepted Answer · 2019-02-25 23:18:07Z

0

Search for the object using .find(). If an object is not returned, use .unshift() to update the array.

let numberArray = [{
    "name": "Smith",
    "number": "088-002-0002",
  },
  {
    "name": "Jhon",
    "number": "088-111-2222",
  },
];

let test = {
  "name": "Smith",
  "number": "088-002-0002",
};



if (!numberArray.find(o => o.number === test.number)) {
  numberArray.unshift(test);
}



console.log(numberArray);

answered Feb 25, 2019 at 23:18

ziggy wiggy

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