How to interpret javascript BN object?

Question

While I was working on smart contract using truffle, whenever request some number like account balance or address from the truffle console; I receive a BN object which looks like this:

BN {
  negative: 0,
  words: [ 37748736, 3305132, 2220446, <1 empty item> ],
  length: 3,
  red: null
}

This object is part of bn.js library. But I am not able to find any documentation on how to interpret this object.

How do I read this. I want to learn what each field in this object means and be able to manually convert it to a normal number.

what is this BN object? That's not a javascript built in - does [this documentation](https://web3js.readthedocs.io/en/v1.2.0/web3-utils.html#bn) help — Jaromanda X, Jun 12 '21 at 06:18
If you are receiving a BN object already, probably you just need to use needed methods to get the number value: bn.toString(base, length), bn.toNumber(), etc — Eddy, Jun 12 '21 at 07:41
I would guess it is [this](https://github.com/indutny/bn.js/) library. — President James K. Polk, Jun 12 '21 at 14:18
The number represented appears to 10000000000000000000000. But this is based on analyzing the *current* internals of the source code. This can change over time, thus you should always use the methods suggested by @Eddy — President James K. Polk, Jun 12 '21 at 14:29

score 4 · Answer 1 · edited Dec 05 '21 at 07:16

4

I am a bit late, but you can convert your function outcome like the following:

outcome = await app.balanceOf(0x....)
outcome.toNumber()

or even better:

(await app.balanceOf(0x....)).toNumber()

edited Dec 05 '21 at 07:16

Dharman

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answered Dec 05 '21 at 07:11

Logan

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score 1 · Answer 2 · answered Jun 13 '21 at 18:31

1

bn.js has a readme with examples.

You can convert the BN object to JS native Number using the .toNumber() function.

answered Jun 13 '21 at 18:31

Petr Hejda

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How to interpret javascript BN object?

2 Answers2