This question arrives early precisely because whoever answers first gives up ground.
The redirect
"I would rather match your range — what has been budgeted for this role?" Roughly half of employers will answer, and a growing number publish it anyway.
The range, if pressed
Give a researched band about 15% wide, with your actual target sitting near the bottom. Negotiation moves down from the top of a range, not up from the middle.
What never to say
Your current salary, if you can avoid it. In several jurisdictions employers cannot ask. Where they can, redirect to what you are targeting for this role.
Common questions
What if they insist on a number?
Give a range with your target near the bottom, and add that you are flexible for the right role.
Should I say I am flexible?
Once, as a closing phrase. Leading with flexibility invites the bottom of the band.