Indicates whether the item expired
isExpired(key)
This method return a boolean
// No expiration
OhMyCache.Local.set('key', 'value')
OhMyCache.Local.isExpired('key') // false
// No expired
OhMyCache.Local.set('key', 'value', {expire: 999999})
OhMyCache.Local.isExpired('key') // false
// Expired
OhMyCache.Local.set('key', 'value', {expire: 1})
// sleep 1 second or more
OhMyCache.Local.isExpired('key') // true