splice first added object in an array when new element is added in javascript

Question

i am working on splicing the old object ie first added object in an array when new element(object) is added in to it automatically.

this is the sample code i worked on

  var sampleArr = [{"id":4,"hostName":"henry"},
                    {"id":3,"hostName":"jeff"},
                      {"id":2,"hostName":"mark"},
                        {"id":1,"hostName":"holder"}];

the above array contains 4 objects when 5 object( {"id":5,"hostName":"punk"}) is added i want to splice first added object ie( {"id":1,"hostName":"holder"}).

here is what i tried in controller

for( var i=0; i<sampleArr.length; i++){
          var index = i;
          if(sampleArr.length > 4){
            sampleArr.splice(index,1,sampleArr[i]);

        } 
        }

but it not working as i expected. please any help me to sought out this!

No need of loop if (arr.length === 4) { arr[0] = newObj; } — Tushar
– Tushar, Commented Oct 7, 2016 at 4:18
splice can do many things. Can you show us what output you expect? — LinuxDisciple
– LinuxDisciple, Commented Oct 7, 2016 at 4:21
var sampleArr = [{"id":4,"hostName":"henry"}, {"id":3,"hostName":"jeff"}, {"id":2,"hostName":"mark"}, {"id":5,"hostName":"punk"}]; — Sukumar MS
– Sukumar MS, Commented Oct 7, 2016 at 4:23
If you were looking for a more... thorough solution, perhaps consider something like stackoverflow.com/questions/1583123/…? — Shadowen
– Shadowen, Commented Oct 7, 2016 at 4:30
do you want first element to remove or the last one coz' {"id":1,"hostName":"holder"} is last element and {"id":4,"hostName":"henry"} is first one. — A.T.
– A.T., Commented Oct 7, 2016 at 5:13

Pranesh Ravi · Accepted Answer · 2016-10-07 04:22:14Z

1

You can use the simple pop() to take out the last element and use push to add a new element into the array!

var sampleArr = [{
  "id": 4,
  "hostName": "henry"
}, {
  "id": 3,
  "hostName": "jeff"
}, {
  "id": 2,
  "hostName": "mark"
}, {
  "id": 1,
  "hostName": "holder"
}];



sampleArr.pop()

sampleArr.push({
  "id": 5,
  "hostName": "punk"
})

console.log(sampleArr)

answered Oct 7, 2016 at 4:22

Pranesh Ravi

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2 Comments

Pranesh Ravi Over a year ago

@SukumarDhoni Of course you can. developer.mozilla.org/en/docs/Web/JavaScript/Reference/…

Sukumar MS Over a year ago

can i push like this sampleArr.push(sampleArr[sampleArr[5]]);

Community · Accepted Answer · 2017-05-23 11:53:06Z

1

You can use unshift to add new item in begin of array and use pop to remove last item in array. Read more here.

Try this:

sampleArr.unshift({"id":5,"hostName":"punk"});
sampleArr.pop();

Hope will helps.

edited May 23, 2017 at 11:53

CommunityBot

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answered Oct 7, 2016 at 4:26

DieuNQ

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1 Comment

Shadowen Over a year ago

See also stackoverflow.com/a/33608379/5195629 for an implementation that wraps this in a function (fairly simple really, but I wanted to include it for completeness).

A.T. · Accepted Answer · 2016-10-07 05:10:18Z

1

I think OP is asking for FIFO (first in first out operation) , since I don't understand how {"id":1,"hostName":"holder"} could be first element in below array. But here is what I suggest.

Array.prototype.performFIFO = function(element) { this.push(element); this.shift(); return this; } 

var sampleArr = [{"id":4,"hostName":"henry"},
                    {"id":3,"hostName":"jeff"},
                      {"id":2,"hostName":"mark"},
                        {"id":1,"hostName":"holder"}];



sampleArr.performFIFO({"id":5,"hostName":"fifth element"})

console.log(sampleArr)

answered Oct 7, 2016 at 5:10

A.T.

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Comments

Vojtech Ruzicka · Accepted Answer · 2016-10-10 16:43:45Z

0

Try this:

sampleArr.splice(sampleArr.length,1,sampleArr[i]);

edited Oct 10, 2016 at 16:43

Vojtech Ruzicka

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answered Oct 7, 2016 at 4:35

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