Separate objects in an array from their index using localstorage

Question

I am looking for a way to separate objects from an array, having only the index avaiable. I have something like this:

     var hello= [];
     for (var i=0; incr.lenght>0; i++;)
     {

        hello+= originalarray[incr[i]].item;

       }

Array: 0: item0 1: item1 2: item2 3: item3

Having this: hello+= originalarray[incr[0,2,3]].item;

I get this: item0item2item3

The "item" comes from another array, this is a small part of my code, but hopefully it's enough to explain my problem. When I create an alert(hello); what I get is a list of item like this: item0item1item2item3. What I am looking for is a way to separate them. But I need to use the localStorage as well, and I was thinking of creating a different key for every value of the index. Hope it makes sense, I am a new user. Thank you very much!

Using `+=` is not how you insert into an array. You are turning everything into a string. Suggest studying some array fundamentals tutorials — charlietfl, Nov 17 '18 at 23:03
@trincot I was thinking of using push, but I haven't figure out yet how to use it with localstorage — heyheyhey, Nov 17 '18 at 23:18
A quick web search for "javascript insert array" would answer that question very quickly — charlietfl, Nov 17 '18 at 23:18
You can also store whole arrays in localstorage. Unfortunately Stackoverflow isn't really a *"how to"* tutorial service and most of what you are trying to do is fairly easy to research — charlietfl, Nov 17 '18 at 23:20
You need to dig into a fundamentals tutorial. No offense man, just trying to help you level up quickly. — Ben Steward, Nov 17 '18 at 23:29

score 0 · Answer 1 · answered Nov 18 '18 at 09:55

First of all, the for loop you have in your question has several issues:

It has three ;, while the syntax only allows two. You need to remove the final one
It has a condition that is never true, because lenght has a spelling mistake. If you correct it it will always be true (infinite loop):
```
incr.length>0
```
This should be:
```
i < incr.length
```

Then the main issue is that you apply a string operator (+=) to concatenate the items, and so hello is no longer an array, but a string:

    hello+= originalarray[incr[i]].item;

Instead you should use push:

    hello.push(originalarray[incr[i]].item);

In order to store hello in localStorage you should not try to make a key for each item and store each separately. Instead use JSON.stringify (for writing) and JSON.parse (for reading) as explained in this Q&A.

Please read again, I wrote it in a negative way: *"It has a condition that is never true"*. Also note I wrote *"If you correct it"* to make the other claim. — trincot, Nov 18 '18 at 10:04

Separate objects in an array from their index using localstorage

1 Answers1