odoo store POS data in browser local storage. 

1. Would like to understand how long can odoo's POS system stores offline transaction for ?
     POS offline data stored in browser local storage. it does not automatically delete/clean
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​2. Will the data/transaction be automatically deleted after a couple of days/weeks/months?
    No, data not automatically deleted periodically. you have to explicitly clean data if you want
 
3. Accidentally closing the POS tab will that also means that we will loose all cache history?​
    No, you don't lose data if you close the browser tab accidentally.

local storage is persistent data storage up to 5MB (limit very dependent on a browser) per domain.

ref :https://developer.mozilla.org/en-US/docs/Web/API/Window/localStorage
​https://blog.logrocket.com/the-complete-guide-to-using-localstorage-in-javascript-apps-ba44edb53a36/ 
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