Remove all items. Also removes read-only datas
clear(onlyExpired = false)
This method return a boolean
OhMyCache.Local.set('key', 'value')
OhMyCache.Local.set('key2', 'value', {readonly: true})
OhMyCache.Local.clear() // true
OhMyCache.Local.get('key') // null
OhMyCache.Local.get('key2') // null