[SOLVED] Is there a helper function in the Midnight JS library to replicate Compact's builtin pad() function?

Is there a helper function in the Midnight JS library to replicate Compact's builtin pad() function?

I'm trying to use the tokenType() function in Midnight's compact language to calculate the TokenType of a new coin. Is there a helper function I can use in the Midnight JS library to replicate Compact's built in pad() function?

I'm struggling with creating a Uint8Array that matches the Bytes<32> Compact type I created with the pad function in my contract. Any suggestions on how to do this?

Solution

To replicate Compact’s pad() function in Midnight JS, you can manually pad a Uint8Array to the desired byte length like so:

function padToBytes32(input: Uint8Array): Uint8Array {
  if (input.length > 32) throw new Error("Input too long for Bytes<32>");
  const padded = new Uint8Array(32);
  padded.set(input, 32 - input.length); // right-align like Compact's pad()
  return padded;
}

This matches Compact’s behavior where values are padded on the left (i.e., right-aligned) with zeros to match the required byte size.