token-js: `createAssociatedTokenAccountIdempotentInstruction` shouldn't require client to pass in `associatedToken`

[metaproph3t]

The handy createAssociatedTokenAccountIdempotentInstruction allows you create instructions that idempotently create associated token accounts. One thing that annoys me about it is that it requires me to pass in the associated token account, like so:

...
.preInstructions([
        createAssociatedTokenAccountIdempotentInstruction(
          this.provider.publicKey,
          token.getAssociatedTokenAddressSync(
            tokenMint,
            pdaOwner,
            true
          ),
          pdaOwner,
          tokenMint
)]
...

I don't see the purpose of this given that associated token accounts can always be derived by the getAssociatedTokenAddressSync. Maybe this function was written before getAssociatedTokenAddressSync existed? In any case, it would be nice if this parameter was made optional or removed entirely.

[joncinque]

The instruction creators like this are meant to be totally customizable, just like createAssociatedTokenAccountInstruction -- if you want to add a helper, PRs are always welcome!

[metaproph3t]

What does customizable mean here? An associated token account pubkey is the result of applying getAssociatedTokenAddressSync to mint and owner, so what's the point of having both mint/owner and associatedToken? I'm trying to understand what use-case this unlocks

[joncinque]

"customizable" just means you can set every possible account in the instruction, even if it's incorrect. If you're particularly performance-sensitive, then this creator allows you to incur the cost of deriving the associated token account address just once rather than being forced to do it multiple times.

But either way, we can definitely add a helper!