javascript update or add values to array

Question

I want to add values to array. But the same values may update. for example my array is

[{"abc1":"123456"},{"abc2":"123456"}]

when is adding again is abc1. It may update. For example in normal case

[{"abc1":"123456"},{"abc2":"123456"},{"abc1":"123456"}]

But i want

[{"abc2":"123456"},{"abc1":"123456"}]

My code

var categories = [],
arrIndex = {};

addOrReplace({"abc1":"125"});
addOrReplace({"abc2":"126"});
addOrReplace({"abc1":"127"});
addOrReplace({"abc3":"129"});


function addOrReplace(object) {
    var index = arrIndex[object[0]];
    console.log("index:"+object[0]);
    if(index === undefined) {
        index = categories.length;
    }
    arrIndex[object[1]] = index;
    categories[index] = object;
}

console.log(categories);

It not showing correct answer. It shows

[{"abc3":"129"}]

I want

[{"abc2":"126"},{"abc1":"127"},{"abc3":"129"}]

How it possible? Please help me?

So if I understand right, if objects with key abc1 exists, delete it and push new value. Am I right? — Rajesh Dixit
– Rajesh Dixit, Commented Apr 20, 2017 at 6:07
If object inside array has only one key, I would suggest to have object than array. Value will be overwritten in Object — Rayon
– Rayon, Commented Apr 20, 2017 at 6:08
@joe — var obj = { a: 1, b: 2 }; obj.a = 3; console.log(JSON.stringify(obj)); — Rayon
– Rayon, Commented Apr 20, 2017 at 6:19

Nina Scholz · Accepted Answer · 2017-04-20 06:52:12Z

2

You could use Array#findIndex ans plice the object from categories if the index is found, then push the new object to categories.

function addOrReplace(object) {
    var key = Object.keys(object)[0],
        index = categories.findIndex(o => key in o);

    if (index !== -1) {
        categories.splice(index, 1);
    }
    categories.push(object)
}

var categories = [];

addOrReplace({ abc1: "125"});
console.log(categories);
addOrReplace({ abc2: "126"});
console.log(categories);
addOrReplace({ abc1: "127"});
console.log(categories);
addOrReplace({ abc3: "129"});
console.log(categories);

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

edited Apr 20, 2017 at 6:52

answered Apr 20, 2017 at 6:22

Nina Scholz

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Comments

Anurag Dadheech · Accepted Answer · 2017-04-20 06:25:22Z

1

   var categories = new Map(); 

    addOrReplace({"abc1":"125"});
    addOrReplace({"abc2":"126"});
    addOrReplace({"abc1":"127"});
    addOrReplace({"abc3":"129"});


    function addOrReplace(object) {
       for (var name in object)
             categories[name] = object;
    }

    console.log(categories);

answered Apr 20, 2017 at 6:25

Anurag Dadheech

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Comments

LeagueOfJava · Accepted Answer · 2017-04-20 06:26:51Z

0

var categories = [],
arrIndex = {};

addOrReplace({"abc1":"125"});
addOrReplace({"abc2":"126"});
addOrReplace({"abc1":"127"});
addOrReplace({"abc3":"129"});


function addOrReplace(object) {
    for(var c in categories){
        if(Object.keys(categories[c])[0] == Object.keys(object)[0]){
            categories.splice(c,1)
        }
    }
    categories.push(object)
}

console.log(categories);
//[{"abc2":"126"},{"abc1":"127"},{"abc3":"129"}]

answered Apr 20, 2017 at 6:26

LeagueOfJava

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Comments

Akshay Soam · Accepted Answer · 2017-04-20 06:32:10Z

0

I don't know how you would be finally using the final data but in case you are looking for the uniqueness, i would like to recommend to go for object hash instead of array.

Initially :

{
    "abc1" : "123456",
    "abc2" : "123456"
}

If you now add { "abc1" : "some_other_value" }.

{
    "abc1" : "some_other_value",
    "abc2" : "123456"
}

You can also check if the value exist already or not using if(objectHash('abc1')).

It can save you from extra traversal and would overwrite values if already present.

answered Apr 20, 2017 at 6:32

Akshay Soam

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