In this tutorial we will:

• Use @superfluid-finance/js-sdk in the truffle console with goerli testnet

• Mint Superfluid DAI (DAIx)

• Check Super Token balances

Installation

Download the example repo, which includes the Superfluid JavaScript software development kit.

git clone https://github.com/superfluid-finance/protocol-monorepo
yarn install
yarn build

If you haven't already, install truffle and jq.

npm i -g truffle
​
# Linux
sudo apt-get install jq
# Mac
brew install jq

Obtain goerli ETH

Before we can get testnet ETH, we need a 12-word mnemonic to create some test wallets. If you don't have a mnemonic, we can use Truffle to create one.

truffle develop
​
> Accounts:
> (0) 0x627306090abab3a6e1400e9345bc60c78a8bef57
> (1) 0xf17f52151ebef6c7334fad080c5704d77216b732
​
> Mnemonic: rigid cradle south ...

Copy the first address and use one of the Görli testnet faucets listed at https://goerli.net/ to obtain some ETH. You can also add it to MetaMask, but please don't use it for mainnet / real tokens! If you opt for the MetaMask method, our dashboard will also send you testnet ETH when logging in.

Now exit from truffle develop, and create a file named .env in packages/ethereum-contracts. Add the mnemonic you just created, and your web3 provider URL for goerli test network.

cd packages/ethereum-contracts 
cp .env.template .env
​
# Add your details
GOERLI_MNEMONIC=rigid cradle south ...
GOERLI_PROVIDER_URL=https://goerli.infura.io/v3/<API_KEY>

Truffle console

We are ready to open the Truffle console. You should be in packages/ethereum-contracts next to your .env file for this step.

npx truffle --network goerli console

Let's load the SDK and initialize it with the contracts.

SuperfluidSDK = require("@superfluid-finance/js-sdk")
​
sf = new SuperfluidSDK.Framework({version: "v1", web3, tokens: ["fDAI"] })
​
await sf.initialize()
​
chainId 5
Resolver at 0x3710AB3fDE2B61736B8BB0CE845D6c61F667a78E
Resolving contracts with version v1
Superfluid host contract: TruffleContract .host @0x22ff293e14F1EC3A09B137e9e06084AFd63adDF9
ConstantFlowAgreementV1: TruffleContract .agreements.cfa @0xEd6BcbF6907D4feEEe8a8875543249bEa9D308E8 | Helper .cfa
InstantDistributionAgreementV1: TruffleContract .agreements.ida @0xfDdcdac21D64B639546f3Ce2868C7EF06036990c | Helper .ida
fDAI: ERC20WithTokenInfo .tokens["fDAI"] @0x88271d333C72e51516B67f5567c728E702b3eeE8
fDAIx: ISuperToken .tokens["fDAIx"] @0xF2d68898557cCb2Cf4C10c3Ef2B034b2a69DAD00

What just happened? The Superfluid SDK used the resolver contract deployed on goerli to fetch all the Superfluid contracts for the version "test". Then the contract objects were created using the Truffle artifacts in the /build folder. Make sure you are using the latest version name!

For this tutorial, we'll be using fake ERC20 tokens called fDAI. If you need more than one token, you can easily add fUSDC and fTUSD as parameters when creating the sf object.

Superfluid SDK created a Truffle object for our test token, and its superToken wrapper, at sf.tokens.fDAI and sf.tokens.fDAIx

Now we'll load a web3 utility library @decentral.ee/web3-helpers and create easy-to-use aliases for our wallet addresses and tokens.

const {
  toWad,
  toBN,
  fromWad,
  wad4human
} = require("@decentral.ee/web3-helpers");
​
const dai = await TestToken.at(sf.tokens.fDAI.address);
const daix = sf.tokens.fDAIx;
​
bob = accounts[0];
alice = accounts[1];
dan = accounts[2];
carol = accounts[3];

Mint some DAIx (Superfluid DAI)

If you used MetaMask and the Superfluid Dashboard with this wallet, then your should already have some DAIx tokens. You can skip ahead to checking balance.

Let's mint bob 100 DAI (in testnet, minting is open for anyone to call).

await dai.mint(bob, web3.utils.toWei("100", "ether"), { from: bob })
​
# Check bob's balance
(async () => (wad4human(await dai.balanceOf(bob))))()
> '100.00000'

Now bob has some normal DAI.

Before we can use DAI with Superfluid, we need to upgrade it to the Superfluid version "DAIx".

This is done using a SuperToken wrapper contract. Generally, there is a single wrapper for each ERC20.

Because we previously got the daix object when initializing the contract, we can now upgrade 50 of bob's DAI by calling approve() followed by upgrade()

dai.approve(daix.address, "1"+"0".repeat(42), { from: bob })
​
daix.upgrade(web3.utils.toWei("50", "ether"), { from: bob })
​

Check Balances

(async () => (wad4human(await daix.balanceOf(bob))))()
> '50.00000'

Hurrah, we now have 50 Superfluid-enabled DAI or "DAIx". We are ready to start using Superfluid.

Up next

Next we'll learn how to stream money in 🔀 Create a Superfluid Flow​