CODEWITHSUNDEEP
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Nate Pet
Nate Pet

Reputation: 46222

HTML5 - window.localStorage retrieve data

I am currently data into a local db as following:

    window.localStorage.setItem('QQIDVAL' + ID, JSON.stringify(this));

How do I go about then retrieving all of the data that is in the localstorage and looking for ones that start with "QQ"

Also how do I go about selecting which columns I want to retreive as JSON.stringify(this) has a lot of columns but I only need a subset of those.

Upvotes: 0

Views: 1843

Answers (4)

Jamund Ferguson
Jamund Ferguson

Reputation: 17014

Many frameworks like Sencha Touch and Backbone have some basic ability simulate DB functionality using localStorage. If you're excited to roll your own solution I would suggest doing something more like this:

// get the user store
var users = getUsers();
var john = user["john1234"];

// get all of the existing users
function getUsers() {
  return JSON.parse(window.localStorage.users) || {};
}

// save users
function saveUsers(users) {
  window.localStorage.users = JSON.stringify(users);
}

// add a user
function addUser(user) {
  var id = user.id || new Date().getTime();
  users[id] = user;
}

So my suggestion is instead of combining things based on a string separate them into separate collections or stores using standard

This is by no means a specific answer to your question but it might help you out!

Upvotes: 0

Julien Lafont
Julien Lafont

Reputation: 7877

You can store an array in your localStorage.

Something like that (i haven't managed the Jsonify. you could use Lawnchair to facilitate theses operations)

window.localStorage.setItem('QQ', {items: [] });

function addItem(id, json) {
  var o = window.localStorage.getItem('QQ');
  o.items[id] = json;
  window.localStorage.setItem(o);
}

function getItem(id) {
  return window.localStorage.getItem('QQ').items[id];
}

function getAllItems() {
   return window.localStorage.getItem('QQ').items;
}

function printAllItems() {
   var all = getAllItems();
   for (id in all) {
     console.log(id +" => "+ all[id]);
   }
}

Upvotes: 1

Elliot Bonneville
Elliot Bonneville

Reputation: 53291

You can take advantage of the fact that localStorage is treated like an object and do something like this (iterating through the keys and checking their name):

​for(dataObj in localStorage) {
    if(dataObj.charAt(0) == Q && dataObj.charAt(1) == Q) {
        // do whatever with your data object, it starts with QQ
        var myObj = localStorage[dataObj];
    }
}​

You could also change the if statement to this:

if(dataObj.substr(0,2) == "QQ") { // do your thing

Don't have a reference to the substr() documentation right now though, don't recall if that's the correct syntax.

Upvotes: 0

Samuli Hakoniemi
Samuli Hakoniemi

Reputation: 19049

You should do this with databases, not storage (which is for key-value pairs). Try googling IndexedDB or Web SQL as keywords.

Upvotes: 0

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