parseEther Throws an error when the value is smaller than 0.001 ETH and has a lot of decimals

[haidarally]

Ethers Version

6.9.0

Search Terms

parse, parseEther, Ether

Describe the Problem

The parseEther helper Throws an error when the value is smaller than 0.001 ETH and has a big amount of decimal places.

For example: "0.0004985398760370963"

I expect it to correctly convert it to wei values.

please see error attached

Code Snippet

ethers.parseEther(A0.toString());

// where A0 is actually "0.0004985398760370963"

Contract ABI

No response

Errors

Error in getExpectedAmountOut RangeError: too many decimals for format (operation="fromString", fault="underflow", value="0.0004985398760370963", code=NUMERIC_FAULT, version=6.9.0)
  at processTicksAndRejections (node:internal/process/task_queues:95:5) {
      code: 'NUMERIC_FAULT',
      operation: 'fromString',
      fault: 'underflow',
      value: '0.0004985398760370963',
      shortMessage: 'too many decimals for format'
    }

Environment

node.js (v12 or newer)

Environment (Other)

No response

[ricmoo]

Yes. That will cause underflow to occur. You should not use JavaScript decimal numbers for any aspect of blockchain, as they will round which almost certainly result in failed interactions.

You should perform any maths needed using the FixedNumber class if you need decimal values, although generally it is better to use integers (using bigint).

You ever find yourself using .toString() on a number you are going to be an unhappy camper in the near future. :)

[ricmoo]

(moving to discussion)