Replace element from first array by another element of second array

Question

I am having this issue replacing element from first array by another element of second array.

For exapmle if I have one array haiving some empty values and string like this:

let array_1 = [empty, 'Connected', empty, 'Connected', 'Connected'];

And another new array will be like this:

let array_2 = [empty, 'Updated'];

So, New updated array with replaced element will look like this:

newArray = [empty, 'Updated', empty, 'Connected', 'Connected'];

I tried with for loop and by using findIndexof, but could not replace the element with exact index address.

One of them which worked for me partially is:

console.log(Object.values(...array_1, ...array_2));

Out of above line is just one array with one element, not reast of element from array_1:

['Updated']

But it seems like Obejct.values() does not work with element generated as a empty.

Any possible solution on this would be great!

mgm793 · Accepted Answer · 2022-05-03 12:46:05Z

3

If I understood it properly you can solve it by using map function like this:

let array_1 = [undefined, "Connected", undefined, "Connected", "Connected"];
let array_2 = [undefined, "Updated"];

const res = array_1.map((val, idx) => {
  return array_2[idx] || val;
});
console.log(res);

answered May 3, 2022 at 12:46

mgm793

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3 Comments

Shriniwas Over a year ago

Could you explain it in brief? that would be nice. And tell how empty element from the array behaves like?

mgm793 Over a year ago

Yeah sure, and empty element in a javascript array is always assigned as undefined, And this map loops the array one and returns or the values of the same position of the array 2 or if the array 2 has no values for this position return the val of the first array

Shriniwas Over a year ago

Execellent! But when I checked with console.log(typeof array2[0]) it showed me undefined, but in for loop or map function it did't show me anything. why?

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