Is there a easy way of deriving the pubkey of an Address Lookup Table?

Question

Usually the flow is

1. createLookupTable
2. Use that lookup table immediately after whilst having access to the pubkey.

But what if I want to prepare an ALT from early on and use that in the future? Are there any smart ways of easily deriving the pubkey from an earlier lookupTable? I.e. as easy as deriving the pubkey from the ALT authority pubkey?

Answer 1

To make it easier to locate the lookup table in the future, you may need to store its address in a different account (using a PDA), as one of the seeds used to derive the address of the lookup table is a recentSlot from when it was created.

https://github.com/solana-labs/solana-web3.js/blob/master/packages/library-legacy/src/programs/address-lookup-table/index.ts#L273

const [lookupTableAddress, bumpSeed] = PublicKey.findProgramAddressSync(
  [params.authority.toBuffer(), toBufferLE(BigInt(params.recentSlot), 8)],
  this.programId,
);