Move to BN.js

[crptm]

Move to BN.js

[wbobeirne]

Looks like this task is going to be a mild pain. I did a little audit of everywhere we use it (As of 8854d42)

We'll likely need to implement a big-numberless way of converting a decimal string into a wei unit string. Fortunately if we switch over to the libs/units classes, I think it should make the bulk of future bignumber handling pretty well contained, aside from gas and a few other instances.

bignumber.js usage

File	Conversion steps
common/actions/deterministicWallets.js	1:1 (Type only)
common/actions/wallet.js	1:1 (Type only)
common/libs/erc20.js	1:1
common/libs/transaction.js	Rework to only use wei
common/libs/units.js	Rework to force everything into wei / use classes
common/reducers/wallet.js	1:1 (Type only)
common/selectors/wallet.js	1:1
common/utils/formatters.js	Likely needs to be moved into libs/units.js, assumes decimals
spec/libs/erc20.spec.js	Reworked to not use decimals
spec/libs/contract.spec.js	Unused
spec/libs/units.spec.js	Reworked to not make bigs from decimals
spec/reducers/wallet.spec.js	1:1
spec/utils/formatters.spec.js	Mostly removed, see common/utils/formatter.js
.../BalanceSidebar/AccountInfo.jsx	1:1 (Type only)
.../BalanceSidebar/EquivalentValues.jsx	Unused
.../BalanceSidebar/index.jsx	Unused
common/libs/nodes/INode.js	1:1 (Type only)
common/libs/wallet/trezor.js	Uncertain, not sure what values a transaction v can be
.../BalanceSidebar/TokenBalances/TokenRow.jsx	1:1 (Type only)
.../SendTransaction/index.jsx	1:1
common/libs/nodes/rpc/index.js	I think token values may need to be reworked, unsure if they come back in "wei"
common/libs/nodes/rpc/utils.js	1:1 (Type only)
spec/libs/nodes/rpc/rpc.spec.js	1:1
.../SendTransaction/components/ConfirmationModal.jsx	Will need to stop using the toUnit function

[dternyak]

@wbobeirne Is this something we still want to do?

[crptm]

We want to do it. We already ship it for ethereumjs, it is much more lightweight and wasn't noticed in infinite loops :)

[dternyak]

It seems ethereumjs libraries have settled on using BN.js as a standard for handling large numbers in JavaScript.

This is not to be confused with bignumber.js

Examples:

• https://github.com/ethereumjs/ethereumjs-util/blob/f53d34aec3213c39d117ddabf25dcbddca13ce83/index.js#L5
• https://github.com/ethereumjs/ethereumjs-abi/blob/4a33f233cc6a2f50c9a8ae59684ba631c4b91825/package.json#L7

Additionally, the MetaMask team uses BN.js.

In the interest of following this de-jure standard, we should switch to BN.js as well. To solve the issue of BN.js not supporting decimimals, amount state will be kept in Wei.

[wbobeirne]

Going to hold off on this until @HenryNguyen5 finishes the typescript changeover, to reduce conflicts.