how to add objects to array in localStorage

Question

I tried the solution posted on this [adding objects to array in localStorage but it doesnt seem to work for me.Mine has a small change,I am getting the values as a list from python flask app:

    var myValue = {{ List|safe }};
    onload=function appendRow() {
    var names = [];
    names = myValue;
    var existingEntries = JSON.parse(localStorage.getItem("allEntries")) || [];
    localStorage.setItem("oltbl", JSON.stringify(names));
    existingEntries.push(oltbl);
    localStorage.setItem("allEntries", JSON.stringify(existingEntries))
    var storedNames = JSON.parse(localStorage.getItem("allEntries"));
    var tbl = document.getElementById('mixed'), 
    row = tbl.insertRow(tbl.rows.length),     
    i;
    for (i = 0; i < tbl.rows[0].cells.length; i++) {
    createCell(row.insertCell(i), storedNames[i], 'row');
     }
     }

    function createCell(cell, text, style) {
    var div = document.createElement('div'), 
    txt = document.createTextNode(text); 
    div.appendChild(txt);                    
    cell.appendChild(div);                  
    }
    </script>
    <body>
    <table id="mixed">
    <tr>
    <th>Title</th>
    <th>Text</th>
    <th>STATUS</th>
    </tr>

Any pointers?

when I have just this: localStorage.setItem("oltbl", JSON.stringify(names)); var storedNames = JSON.parse(localStorage.getItem("oltbl")); It rewrites evrytime the function gets called. I want to maintain a table everytime this page is rendered. — Carmel Jacob
– Carmel Jacob, Commented Sep 27, 2017 at 9:49
it should be var storedNames = JSON.parse(localStorage.getItem("allEntries")); instead of var storedNames = JSON.parse(localStorage.getItem("oltbl")); and oltbl is not defined, so you push nothing into your array — Olivier Boissé
– Olivier Boissé, Commented Sep 27, 2017 at 9:56
@oliv37 I have it like "JSON.parse(localStorage.getItem("allEntries"))" in my code,this was done just for testing purpose. — Carmel Jacob
– Carmel Jacob, Commented Sep 27, 2017 at 10:02

Daniel Maiochi · Accepted Answer · 2017-09-27 10:07:25Z

0

You're always setting the allEntries the result of itself, but since you never set a thing to it, it's blank

You should rethink what exactly what you want to achieve.

also

existingEntries.push(oltbl); /*oltbl IS NOT ASSIGNED*/

and causes js error

answered Sep 27, 2017 at 10:07

Daniel Maiochi

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7 Comments

Carmel Jacob Over a year ago

Ok,Can I have it set as an array var oltbl=[]; localStorage.setItem("oltbl", JSON.stringify(names)); This prints out [object Object] in the html page. Basically I need to add entries of some values returned by flask app in the table without overwriting.

Daniel Maiochi Over a year ago

So you need to update your allEntries adding some new values?

Carmel Jacob Over a year ago

yes each time new values get added to the array Ive removed allEntries and tried printing the existingEntries array and this is what i got: localStorage.setItem("entry", JSON.stringify(entry)); existingEntries.push(entry); document.getElementById('whereToPrint').innerHTML = JSON.stringify(existingEntries); var retrievedData = JSON.parse(localStorage.getItem("existingEntries")); document.getElementById('whereToPrint1').innerHTML = JSON.stringify(retrievedData); existingEntries array gets printed,but retrievedData prints null.any idea why?

Daniel Maiochi Over a year ago

check your local storage using the chrome inspector window for example. open it (F12) > Application > Local Storage and see if you have what you expect

Carmel Jacob Over a year ago

Hi Daniel, I am able to see the entries getting populated in LocalStorage->allEntries but when printing on html page it just shows up like this []

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