Feature suggestion: allow more seed types to be provided to getProgramDerivedAddress()

[mikemaccana]

For

solana-web3.js/packages/addresses/src/program-derived-address.ts

Line 80 in 273bc9e

type Seed = Uint8Array | string;

, if I read this correctly, I don't have to do Buffer.from("someString") when running getProgramDerivedAddress() since ProgramDerivedAddressInput includes strings so I can just provide the string directly, avoiding the need to write boilerplate.

What if we allowed Addresses, BigInts etc? If an Address is provided as a seed, encode it as a byte array.

Motivation + Example use case

When working with web3.js 1.x code, I notice a lot of boilerplate encoding code:

Before

const pdaAndBump = PublicKey.findProgramAddressSync(
  [
    Buffer.from("somestring"),
    userKeypair.publicKey.toBuffer(),
    id.toBuffer("le", 8),
  ],
  programKeypair.publicKey
);

So wrote a little wrapper that follows this technique, checking for different types end consistently encoding them:

After

const pdaAndBump = getPDAAndBump(
   ["somestring", userKeypair.publicKey, id],
   programKeypair.publicKey
);

Details

For your own reference, this is what my own getPDAAndBump()looked like, I'm sure you could write something better though:

// A generic function to take strings, publickeys, and BNs
// does whatever work is necessary to turn them into PDAs
export const getPDAAndBump = (
  // @ts-ignore this type exists
  inputs: Array<string | PublicKey | BN>,
  programId: PublicKey
) => {
  const buffers = inputs.map((input) => {
    if (typeof input === "string") {
      return Buffer.from(input);
    }
    // TODO: not sure why instanceof occasionally doesn't work
    // fix it and get rid of the constructor hack
    if (input instanceof PublicKey || input.constructor.name === "PublicKey") {
      return input.toBuffer();
    }
    // @ts-ignore this type exists
    if (input instanceof BN) {
      return input.toBuffer("le", 8);
    }
    throw new Error("getPDAAndBump: unsupported type");
  });
  const programAddressAndBump = PublicKey.findProgramAddressSync(
    buffers,
    programId
  );
  return programAddressAndBump;
};