Might be a stupid question but when you use your reaction to give your familiar resistance to a damage type, how long does this resistance last?

Investment of the Chain Master

Prerequisite: Pact of the Chain feature

When you cast find familiar, you infuse the summoned familiar with a measure of your eldritch power, granting the creature the following benefits:

• The familiar gains either a flying speed or a swimming speed (your choice) of 40 feet.
• As a bonus action, you can command the familiar to take the Attack action.
• The familiar’s weapon attacks are considered magical for the purpose of overcoming immunity and resistance to nonmagical attacks.
• If the familiar forces a creature to make a saving throw, it uses your spell save DC.
• When the familiar takes damage, you can use your reaction to grant it resistance against that damage.

It is agaisnt that damage meaning if they take 2 damage, they take 1, the next hit they take without your reaction will be 2 full damage.

Thank you.

No problem, if you have any more questions let me know