session-storage

This is a small utility class for storing and retrieving complex values from sessionStorage. By default, sessionStorage only saves strings. But by using JSON.stringify() and JSON.parse(), we can save objects, arrays, nulls, Booleans, numbers, and strings. And when using the getItem() method, it will retrieve those values in their native type.

This package also fails gracefully (and silently) in those instances where there is no sessionStorage available in the client. One example where this can happen is when a user's browser is in Incognito Mode. In such cases, this package will use a simple session object to store the values temporarily. This will provide some semblance of sessionStorage-like behavior, even if those values will not be present in the next session.

Due to the limitations of JSON.stringify() and JSON.parse(), the integrity of retrieved values cannot be maintained for certain complex values. Specifically, functions will not survive the JSON.stringify()/JSON.parse() process.

Usage

import { session } from '@toolz/session-storage';

session.setItem('theAnswer', 42); // sets the value 42 in sessionStorage
session.getItem('theAnswer'); // returns the number 42

Methods

.clear()

.clear() empties all values from sessionStorage.

const API = {
   arguments: {},
   returns: void,
}

Examples:

session.setItem('one', 1);
session.setItem('two', 2);

session.clear();

session.getItem('one'); // returns NULL
session.getItem('two', 22); // return 22

.getItem()

.getItem() retrieves an item from sessionStorage in its native data type. If it doesn't exist and no default value is provided, it returns NULL. If a default value is provided and the item doesn't exist, it sets the default value as the item and returns that value.

const API = {
   arguments: {
      itemName: {
         required,
         format: 'populated string',
      },
      defaultValue: {
         optional,
         format: any,
      },
   },
   returns: any,
}

Examples:

session.setItem('foo', [1, 2, 3]);
session.setItem('firstName', 'Joe');
session.setItem('address', {street: '101 Main', city: 'fooville'});

session.getItem('foo'); // returns [1, 2, 3]
session.getItem('firstName'); // returns 'Joe'
session.getItem('address'); // returns {street: '101 Main', city: 'fooville'}
session.getItem('notSet'); // returns NULL
session.getItem('anotherNotSet', 3.14); // returns 3.14

.removeItem()

.removeItem() unsets an item from sessionStorage. If the item didn't previously exist, the method throws no error.

const API = {
   arguments: {
      itemName: {
         required,
         format: 'populated string',
      },
   },
   returns: true,
}

Examples:

session.setItem('foo', [1, 2, 3]);
session.setItem('firstName', 'Joe');

session.removeItem('foo');
session.removeItem('firstName');

session.getItem('foo'); // returns NULL
session.getItem('firstName', 'Mary'); // return 'Mary'

.setItem()

.setItem() sets an item into sessionStorage. If the item already existed, it will overwrite the previous one. If the item did not exist, it will create a new item.

const API = {
   arguments: {
      itemName: {
         required,
         format: 'populated string',
      },
      itemValue: {
         optional,
         format: any,
      },
   },
   returns: any,
}

Examples:

session.setItem('foo', [1, 2, 3]);
session.setItem('firstName', 'Joe');

session.getItem('foo'); // returns [1, 2, 3]
session.getItem('firstName', 'Mary'); // return 'Joe'