viem-erc20/src/public/allowance.ts

Viem extensions for erc20 tokens

import { type Address, type Client, erc20Abi, isAddress } from "viem";
import { readContract } from "viem/actions";

export const getErc20TokenAllowance = async function (
  client: Client,
  parameters: { address: Address; owner: Address; spender: Address },
) {
  const { address, owner, spender } = parameters ?? {};

  if (!isAddress(address)) {
    throw new Error("Invalid address");
  }
  if (!isAddress(owner)) {
    throw new Error("Invalid owner address");
  }
  if (!isAddress(spender)) {
    throw new Error("Invalid spender address");
  }

  return readContract(client, {
    abi: erc20Abi,
    address,
    args: [owner, spender],
    functionName: "allowance",
  });
};