Push value in empty index in array

Question

i want to push à value in array , but not at the end, not at the start, at the first empty index

Show the code exemple:

var test=new Array();
test[0]="Lionel";
test[2]="Jhon";
test.push("Cloé");

result:

[ 'Lionel', <1 empty item>, 'Jhon', 'Cloé' ]

And i need to have Cloé just after Lionel Thanks

Edit this is different to insert in specific index, because i can't know the number of empty index, this is slot system . And i just wanna know if we have native solution ? .

Answer 1

You could search for a sparse index and return this index for inserting a value.

 function getIndex(array) { var last = 0; array.some(function (_, i) { return last < i || !++last; }); return last; } var test = ["Lionel", , "Jhon"]; test[getIndex(test)] = "Cloé"; console.log(test); 

Answer 2

You could write a simple function to look for a gap with undefined as the value and place the new value if if found - otherwise just push to the end of the array

function insertFirstGap(array, value){
    for(var i = 0;i<array.length;i++){
        if(array[i] === undefined){
            array[i] = value; 
            return; 
        }
    }
    array.push(value);

}

Live example below:

 var test=new Array(); test[0]="Lionel"; test[2]="Jhon"; insertFirstGap(test,"Cloé"); console.log(test, test.length); function insertFirstGap(array, value){ for(var i = 0;i<array.length;i++){ if(array[i] === undefined){ array[i] = value; return; } } array.push(value); } 

Answer 3

you can do it in the following way

 var test=new Array(); test[0]="Lionel"; test[2]="Jhon"; let x = test.length; Object.keys(test).forEach(function(element, idx){ if(element != idx){ x = (x==test.length ? idx: x); } }) test[x] = "Cloe" console.log(test); 

Answer 4

Solution 1

If you know which index you want to apply the value to, use test[x] = "Cloe" .

Solution 2

If you want to apply the value to the first empty item, use a for loop that goes through every item in the array until it finds one that's empty.

 test = ["Lionel", "", "Jhon", ""]; for (var i = 0; i < test.length; i++) { if (!test[i]) { test[i] = "Cloe"; break; } } console.log(test) 

EDIT:

If you only want to use native functions. Use splice and indexOf .

 test = ["Lionel", "", "Jhon", ""]; test.splice(test.indexOf(""), 1, "Cloe") console.log(test) 

test.splice(index, 1, item) inserts item into test at the specified index . indexOf("") search for an array with no value in it and return its position.

Answer 5

Ok, we don't have native solution, this is my solution with code, my final objective is slot systeme :

 FindValidSocket(Type){
    let count=0;
    while (count!==this.Max[Type]){
        if(typeof(this.traitement[Type][count])==="undefined"){
            return count;
        }else{
            count++;
        }
    }
    return false;
}

Thanks all for your response

Answer 6

function insertIntoFirstEmpty(val, arr) {
   for(var i = 0;i<arr.length;i++) {
      if(typeof arr[i] === 'undefined')
      {
         arr[i] = val;
         return;
      }
   }
   arr.push(val);
}