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# Shield.prototype.runningOn

▸ **runningOn**(): `boolean`

Returns whether we are currently operating on the given shield.

Technically, this may also return true in very isolated incidents in which Fastly is routing traffic from the target shield POP to the POP that this code is running on, but in these situations the results should be approximately identical.

(For example, it may be the case that you are asking to shield to ‘pdx-or-us’. But, for load balancing, performance, or other reasons, Fastly is temporarily shifting shielding traffic from Portland to Seattle. In that case, this function may return true for hosts running on ‘bfi-wa-us’, our Seattle site, because effectively the shield has moved to that location. This should give you a slightly faster experience than the alternative, in which this function would return false, you would try to forward your traffic to the Portland site, and then that traffic would be caught and redirected back to Seattle.)
