bnorton/local-storage

:left_luggage: A simplified localStorage API that just works

local-storage

A simplified localStorage API that just works

Install

Using npm

npm install local-storage --save

Using bower

bower install localstorage --save

API

The API is a simplified way to interact with all things localStorage. Note that when localStorage is unsupported in the current browser, a fallback to an in-memory store is used transparently.

For that reason, consider that local-storage values might evaporate across page views.

ls(key, value?)

If a value argument is provided, acts as ls.set. When value isn't provided, acts as ls.get.

Example

var ls = require('local-storage');

ls('foo');
// <- null

ls('foo', 'bar');
// <- true

ls('foo');
// <- 'bar'

ls.get(key)

Returns value under key in local storage. Equivalent to ls(key). Internally parses the value from JSON before returning it.

Example

var ls = require('local-storage');

ls('foo', 'bar');
// <- true

ls.get('foo');
// <- 'bar'

ls.set(key, value)

Persists value under key in local storage. Equivalent to ls(key, value). Internally converts the value to JSON.

Returns whether an error was thrown by the browser when trying to persist the value. Failure typically means a QuotaExceededError was thrown.

Example

var ls = require('local-storage');

ls.set('foo', 'bar');
// <- true

ls.get('foo');
// <- 'bar'

ls.remove(key)

Removes key from local storage. Returns true if the property was successfully deleted, and false otherwise.

Example

var ls = require('local-storage');

ls.set('foo', 'bar');
// <- true

ls.remove('foo');
// <- true

ls.clear()

Clears local storage.

Example

var ls = require('local-storage');

ls.set('foo', 'bar');
ls.set('baz', 'tar');
ls.clear();

ls.backend(store?)

If a store argument is provided, it sets the backend storage engine. Otherwise it returns the current backend.

Example

var ls = require('local-storage');

ls.backend(sessionStorage);
ls.set('baz', 'tar');
/* close the tab, then reopen */
ls.get('baz');

ls.on(key, fn)

Listen for changes persisted against key on other tabs. Triggers fn when a change occurs, passing the following arguments.

• value: the current value for key in local storage, parsed from the persisted JSON
• old: the old value for key in local storage, parsed from the persisted JSON
• url: the url for the tab where the modification came from

Example

Open a page with the following snippet in multiple tabs. The storage event will trigger on all tabs except for the one that persisted the change.

var ls = require('local-storage');

ls.on('foo', storage);
ls.set('foo', 'bar');

function storage (value) {
  console.log('some other tab changed "foo" to ' + value);
}

ls.off(key, fn)

Removes a listener previously attached with ls.on(key, fn).

Example

var ls = require('local-storage');

ls.on('foo', storage);
ls.off('foo', storage);

function storage (value) {
  console.log('some other tab changed "foo" to ' + value);
}

License

MIT