session-helper

Session-Helper

Session Helper is a module that helps you save a timestamp as an 'expiry time' to your local/session storage to be able to perform checks against it and to trigger callbacks when this expiry time has been reached.

Usage

0) Install

npm install session-helper --save

1) initialize the session helper with a unique id so that it does not conflict with others also using this package

// es6
import SessionHelper from 'session-helper'

export default new SessionHelper(
  "123-my-unique-id-here",    // uuid
  "localStorage",             // cache location: choose between 'localStorage' or 'sessionStorage'
  30,                         // timeout in minutes
  true,                       // debugMode, 'false' by default, enable it to push log messages to console
)

// es5
const SessionHelper = require('session-helper')

const sessionHelper = new SessionHelper(
  "123-my-unique-id-here",    // uuid
  "localStorage",             // cache location: choose between 'localStorage' or 'sessionStorage'
  30,                         // timeout in minutes
  true,                       // debugMode, 'false' by default, enable it to push log messages to console
)

2) use the following methods to manipulate your session/local storage

expiry

Function to get expiry from storage: let expiryFromStorage = SessionHelper.expiry

setExpiry

Function to set expiry from storage: SessionHelper.setExpiry()

removeExpiry

Function to remove expiry from storage: SessionHelper.removeExpiry()

isTokenExpired

Boolean to check if expiry in storage is set and is expired: let isTokenExpired = SessionHelper.isTokenExpired

isTokenExpiredOrNull

Boolean to check if expiry in storage is set and if it is expired, or if it is not even set: let isTokenExpiredOrNull = SessionHelper.isTokenExpiredOrNull

Important: It can be null when, for example, there are two tabs (or more) open and the first tab has called removeExpiry() before the second. Then the expiry will be null in the second, meaning the Session Helper would interpret it as "it is not set" instead of "it is set and expired" because of the other tab. This might be useful when an expiry had to log out a user in the first tab and thus in the second there can be checked if the user is still logged in or not by checking the isTokenExpiredOrNull boolean.

expiryTimeout

Boolean to get the amount of time left in seconds until the expiry is reached (if the timer has started and the callback is set): let timeLeftUntilExpiryIsReached = SessionHelper.expiryTimeout

expiryTimeoutCallback

Variable to set a callback function which will trigger when the timeout function ends:

SessionHelper.expiryTimeoutCallback = function() {
  console.log('Expiry has been reached')
  // perform actions like a logout
}

To get the callback function which will be triggered at the end of the timeout function: let callback = SessionHelper.expiryTimeoutCallback

You can trigger this callback manually by adding extra parentheses like so: SessionHelper.expiryTimeoutCallback()

startExpiryTimeout

Function to start the timeout function, using the timeoutInMinutes configuration parameter: SessionHelper.startExpiryTimeout()

stopExpiryTimeout

Function to stop the timeout function: SessionHelper.stopExpiryTimeout()

resetExpiryTimeout

Function to restart the timeout function, using the timeoutInMinutes configuration parameter. Internally it's simply calling .stopExpiryTimeout and .startExpiryTimeout: SessionHelper.resetExpiryTimeout()

TODO

• add tests
• catch situations where the timeout is being started/reached but there is no callback set
• add pause functionality
• add functionality to poll the session/local storage and to trigger a callback based on the polled results instead of the timeout function
• add link(s) to blogpost(s)
• proposal: refactor the expiryTimeout to time in seconds instead of in minutes (something for v2)

Contributing

PRs are more than welcome and will be reviewed asap!

License

MIT - For full license see the LICENSE file.