Storing compressed json data in local storage

Question

I want to store JSON data in local storage. Sometimes data stored could be more than 5MB(max threshold allowed by browsers for each domain). Is there anyway i can compress or zip the data and store it in local storage ? How much latency it will add if compression and decompression for every JS function on large data ?

I am using this json data to display on webpage..... It is like a static data which is mostly same for entire session. we provide actions like search, filter etc on this json data...Whenever user enters a keyword, i search in this json data which is stored in local storage instead of making call to server

Answer 1

As localStorage functionality seems to be limited to handle only string key/value pairs what you can do is to use lz-string library to stringify the json object and compress it before storing it in localStorage

Usage

// sample json object var jsonobj = {'sample': 'This is supposed to be ling string', 'score': 'another long string which is going to be compressed'}  // compress string before storing in localStorage     localStorage.setItem('mystring', LZString.compress(JSON.stringify(jsonobj)));  // decompress localStorage item stored var string = LZString.decompress(localStorage.getItem('mystring'))  // parse it to JSON object JSON.parse(string); 

Check jsfiddle http://jsfiddle.net/raunakkathuria/7PQtC/1/ as i have copied the complete script so look for running code at end of fiddle

Use compressToUTF16 and decompressFromUTF16 if you are dealing with UTF characters but please note that the strings produced are therefore 6.66% bigger than those produced by compress. So use utf ones only when required.