About minting and decimal

Question

I have 2 instruction. the goal is to create new SPL token, 1,000,000 initial supply with 6 decimal precision.

const initializeMintIx = createInitializeMintInstruction(
  mint.publicKey,
  6, // decimal come from text input
  owner, // mint authority
  owner, // freeze authority
  TOKEN_2022_PROGRAM_ID,
);

const mintToIx = createMintToInstruction(
  mint.publicKey,
  tokenAccount,
  owner,
  1_000_000, // amount. I'm confused on this number
  [],
  TOKEN_2022_PROGRAM_ID,
);

what number should I put on amount in createMintToInstruction param? my current formula for amount is:

tokenSupply * (10 ** tokenDecimal)

is this the correct formula?

I'm trying to fix this: Circulating supply wrong on solana fm?. maybe there's something wrong on my amount formula. thx

Answer 1

Yep you have it correct! Just be careful about using a number that can be properly represented by a JS number, which is 9007199254740991.

More info at https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_SAFE_INTEGER