Experimental: Add a function to get the addresses for lookup tables

[mcintyre94]

Motivation

We have a type AddressesByLookupTableAddress which stores the addresses for lookup tables. I used this in the deserialize-transaction example. To get this you need to write code like:

// The only data from the lookup table we need is its addresses
type LookupTableData = {
    addresses: Address[];
};

// We fetch the JSON parsed representation of the lookup table from the RPC
const lookupTableAccount = await fetchJsonParsedAccount<LookupTableData>(rpc, LOOKUP_TABLE_ADDRESS);
assertAccountDecoded(lookupTableAccount);
assertAccountExists(lookupTableAccount);

const lookupAddresses = {
    [LOOKUP_TABLE_ADDRESS]: lookupTableAccount.data.addresses,
}

We could write a helper function that does this for you, with better error handling, perhaps for multiple lookup tables.

Example use case

const lookupAddresses = await fetchAddressesForLookupTableAddresses(rpc, [LOOKUP_TABLE_ADDRESS])

// compress a transaction message using the lookup tables
const transactionMessageWithLookupTables = compressTransactionMessageUsingAddressLookupTables(transactionMessage, lookupAddresses);

We also use the same data structure for decompileTransactionMessage

Details

• Use await fetchJsonParsedAccounts
• Add assertions that the accounts are owned by the Lookup Table Program
• Add specific errors for the assertions