Clash Royale CLAN TAG

Appending localStorage with dynamic content

I am generating image coordinates at various locations within a image which I am saving to a localStorage item. For example:

var coords = ;
coords.push(Math.round(dragStopLocation.x),Math.round(dragStopLocation.y));


The above stores the values in coords variable. I am setting this to localStorage using:

localStorage.setItem('coords', JSON.stringify(coords));


This as a standalone code works well.

Since, the item coords is dynamic and many arrays of coords is possible, I want to append the item coords with new arrays. I am using the following code:

coords

coords

coords

//Save the original coords items in a variable

var old_coords = localStorage.getItem('coords');


//append

if (old_coords === null) {
localStorage.setItem('coords', JSON.stringify(coords));
} else {
localStorage.setItem('coords', old_coords + JSON.stringify(coords));
}


I tried one more variation of this by including a comma between old_coords and coords

localStorage.setItem('coords', old_coords + ',' + JSON.stringify(coords));


The problem I am facing is when I am trying to get the items of the coords from a different function.

function getArray() {

items = JSON.parse(localStorage.getItem('coords'));

var size = 9;
var newarr = ;
for (var i = 0; i < items.length; i+=size) {
newarr.push(items.slice(i, i+size));
}
return newarr;
}


This is were I am facing the following error:

Uncaught SyntaxError: Unexpected token [ in JSON at position 4


When I use a comma, I get the same error but instead of '[ I get ,.

[

,

I tried replicating this with a simple example:

localStorage.removeItem('items');

function appendToStorage(name, data){
var old = localStorage.getItem(name);
if(old === null || old === undefined) {
localStorage.setItem(name,data);
} else {
localStorage.setItem(name, old +"," + data);
}
}

items1 = ['image1','place','name',10,20,30,40,50,60];
appendToStorage('items', items1);
localStorage.getItem('items');

items2 = ['image2','place','name',11,21,31,41,51,61]
appendToStorage('items', items2);
localStorage.getItem('items');


This works perfectly...however the original code gives errors.

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