Push JSON Objects to array in localStorage

Question

I have a function in Javascript   var a       function SaveDataToLocalStorage data               var receiveddata   JSON stringify data       a push receiveddata       alert a        localStorage setItem  session   a        the data parameter is a JSON Object    But everytime I click the button it overwrites the data in my localstorage   Does anybody know how to do this

User · Answer

Putting a whole array into one localStorage entry is very inefficient: the whole thing needs to be re-encoded every time you add something to the array or change one entry.

An alternative is to use http://rhaboo.org which stores any JS object, however deeply nested, using a separate localStorage entry for each terminal value. Arrays are restored much more faithfully, including non-numeric properties and various types of sparseness, object prototypes/constructors are restored in standard cases and the API is ludicrously simple:

var store = Rhaboo.persistent('Some name');
store.write('count', store.count ? store.count+1 : 1);

store.write('somethingfancy', {
  one: ['man', 'went'],
  2: 'mow',
  went: [  2, { mow: ['a', 'meadow' ] }, {}  ]
});  
store.somethingfancy.went[1].mow.write(1, 'lawn');

BTW, I wrote it.

User · Answer

As of now  you can only store string values in localStorage  You ll need to serialize the array object and then store it in localStorage   For example    localStorage setItem  session   a join          or  localStorage setItem  session   JSON stringify a

User · Answer

There are a few steps you need to take to properly store this information in your localStorage  Before we get down to the code however  please note that localStorage  at the current time  cannot hold any data type except for strings  You will need to serialize the array for storage and then parse it back out to make modifications to it   Step 1  The First code snippet below should only be run if you are not already storing a serialized array in your localStorage session variable  To ensure your localStorage is setup properly and storing an array  run the following code snippet first   var a       a push JSON parse localStorage getItem  session      localStorage setItem  session   JSON stringify a      The above code should only be run once and only if you are not already storing an array in your localStorage session variable  If you are already doing this skip to step 2   Step 2   Modify your function like so   function SaveDataToLocalStorage data        var a              Parse the serialized data back into an aray of objects     a   JSON parse localStorage getItem  session                  Push the new data  whether it be an object or anything else  onto the array     a push data          Alert the array value     alert a       Should be something like  Object array         Re-serialize the array back into a string and store it in localStorage     localStorage setItem  session   JSON stringify a        This should take care of the rest for you  When you parse it out  it will become an array of objects   Hope this helps

User · Answer

var arr      a    b    c    arr push  d       insert as last item

User · Answer

One thing I can suggest you is to extend the storage object to handle objects and arrays   LocalStorage can handle only strings so you can achieve that using these methods  Storage prototype setObj   function key  obj        return this setItem key  JSON stringify obj     Storage prototype getObj   function key        return JSON parse this getItem key       Using it every values will be converted to json string on set and parsed on get

[javascript] Push JSON Objects to array in localStorage

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