Migration to Version 1.0

The SOR Version 1.0.0-0 introduces breaking changes but should be fairly easy to update. Benefits of updating include - support for multihop swaps and an easier to use wrapper interface as well as more efficient/faster processing.

Overview Of Changes

SOR Library

The SOR is now instantiated as an object:

const SOR = new sor.SOR(Provider, GasPrice, MaxPools, ChainId, PoolsUrl)

• Find further details on parameters here.

SOR now has three main functions:

await SOR.setCostOutputToken(tokenOut)

• Calculates gas cost for swapping token on Balancer.

• The result is used to make more gas efficient swap recommendations.

• Result is cached for future use but can be updated by re-calling.

• Notice that outputToken is tokenOut if swapType == 'swapExactIn' and tokenIn if swapType == 'swapExactOut'

const isSuccess = await SOR.fetchPools()

• This fetches all Balancer pool information and on-chain balances.

• Retrieves pool information from static IPFS file rather than Subgraph.

• Retrieves on-chain balances using custom multicall contract.

• Returns true on success or false on error.

• Information is cached and used for all future processing, this results in fast processing of swaps, i.e. useful when changing swap amounts or types in a UI.

• Accurate/valid swaps rely on upM to date balance information so it is recommended this function is re-called to refresh as needed.

const [swaps, amount] = await SOR.getSwaps(tokenIn, tokenOut, swapType, swapAmount)

• Main function to process trade.

• Will return amount expected and a list of swaps that can be executed on-chain.

ExchangeProxy Contract

A new ExchangeProxy contract that supports multihop swaps has been deployed to the addresses below. For contract details please see Exchange Proxy.

• Mainnet: 0x3E66B66Fd1d0b02fDa6C811Da9E0547970DB2f21

• Kovant: 0x4e67bf5bD28Dd4b570FBAFe11D0633eCbA2754Ec

Further Information

• For more information on SOR functions and to see code examples (including using with ExchangeProxy) please see Development & Examples.

• For a full example demonstrating use of SOR wrapper please see here.

• There is also an example showing how the SOR functions can be used without the wrapper.