How to add instructions to a builder with a loop

Question

I'm having issues adding multiple instructions to the builder with a loop.

for (let token of selectedTokens) {

            ...

            const burnIx = burn(umi, {
                ...assetWithProof,
                leafOwner: publicKey(walletPubKey),
            });

            builder.add(burnIx);
        }

When i log the burnIx to the console it's okay, but after the loop if i log the builder the items array is empty.

Answer 1

you need to reassign the builder. e.g. (untested)

let builder = new TransactionBuilder();
for (let token of selectedTokens) {
  const burnIx = burn(umi, {
    ...assetWithProof,
    leafOwner: publicKey(walletPubKey),
    });
  builder = builder.add(burnIx);
}