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SDK Introduction

Overrides

All API functions that produce a signed transaction can be equipped with the usual ethers.js overrides as optional parameters.

Mangrove​

The root class of the API. Use Mangrove.connect to get an instance of it. Here are a few possibilities:

mgv = await Mangrove.connect(window.ethereum); // web browser
mgv = await Mangrove.connect('http://127.0.0.1:8545'); // HTTP provider
mgv = await Mangrove.connect(); // Uses Ethers.js fallback mainnet (for testing only)
mgv = await Mangrove.connect('rinkeby'); // Uses Ethers.js fallback (for testing only)
// Init with private key (server side)
mgv = await Mangrove.connect(
'https://mainnet.infura.io/v3/_your_project_id_', // provider
{
  privateKey: '0x_your_private_key_', // preferably with environment variable
});
// Init with HD mnemonic (server side)
mgv = await Mangrove.connect( {
  signer: myEthersWallet
});

You can test you are indeed connected to the deployed Mangrove by asking for the current global configuration of Mangrove:

config = await mgv.config()

The mgv object gives you access to a variety of useful properties, such as Token, Market and OfferLogic (allowing one to connect to an on-chain offer logic).

info

mgv.contract gives access to the underlying ethers.js contract object, and allows you to interact with the deployed Mangrove using low-level ethers.js calls. Hence, 

await mgv.contract.f(...)

will execute the ethers.js call to the function f on the Mangrove contract (signed when needed by the signer provided to the connect function).

Token​

This class provides easy means to interact with a deployed contract on the standard EIP-20. To obtain an instance use:

tkn = await mgv.token("<symbolOrId>"); // e.g "DAI", "WETH", "amDAI", etc.

using the symbol or id's defined for ERC-20's in the Mangrove context-addresses repo. The relevant specifications are in ERC-20.json). This is also the source of the token addresses given here: Token addresses.

A token object can also be obtained directly via an address:

tkn = await mgv.tokenFromAddress("<tokenAddress>");

With this tkn object you have access to standard calls using human readable input/outputs. For instance:

await tkn.approve("<spender>"); // gives infinite approval to spender
await tkn.approve("<spender>",0.5); // gives allowance to spend 0.5 token units to spender
await tkn.contract.approve("<spender>", tkn.toUnits(0.5)); // ethers.js call

Note that Mangrove's API deals with token decimals automatically (using the definitions given in the context-addresses repo).

info

Token.contract gives access to the ethers.js contract allowing one to interact with the deployed contract using low level calls (for instance if the token has functions that are do not belong to the ERC20 standard).

Market​

The Market class is an abstraction layer to interact with Mangrove markets.

Working as a liquidity taker, it provides access standard market buy and sell orders. The Market methods also provides access, through the buy and sell methods, to post and interact with markets providing liquidity through resting orders. Please refer to the documentation for the TradeParams parameter of the buy and sell methods, for more details.

To obtain an instance of Market use:

//connect to a (base,quote) market with default options
mgvMarket = await mgv.market({base:"<symbolOrId>" | Token, quote:"<symbolOrId>" | Token, tickSpacing: number});

// connect to the market, caching at least the specified number of ticks
mgvMarket = await mgv.market({base:"<symbolOrId>" | Token, quote:"<symbolOrId>" | Token, tickSpacing: number, targetNumberOfTicks: 50});

where %%tickSpacing|tickSpacing%% is defined as explained on the page about Ticks, ratios, and prices for the core Mangrove protocol.

info

Upon connection to a market, the API subscribes to events emanating from Mangrove in order to maintain a local cache of the order book. One may increase the size of the cache by using mgv.market({..., targetNumberOfTicks:<number of ticks to cache>}). It is guaranteed that if at least one offer with a tick is in the cache, then all offers with that tick are in the cache. For more on ticks, please refer to the page on Ticks, ratios, and prices.

For debugging purpose, the class provides a console of the current state of bids and asks posted on Mangrove. For instance to display the bid offers on Mangrove on this market:

// Pretty prints to console the bid offers, showing offer `id`, offer `gives` and offer `price`
await mgvMarket.consoleAsks(["id", "gives", "price"]);

Market instances allow one to subscribe to markets events using:

const f (event) => ...; // what you want to do when receiving the event 
mgvMarket.subscribe(f);

To unsubscribe f from market events simply use mgvMarket.unsubscribe(f).

Market events are records that contain a wealth of information about what happens on the subscribed Mangrove market. Important examples are:

  • OfferWrite with key fields: {olKeyHash: string, maker: string, tick: BigNumber, gives: BigNumber, gasprice: BigNumber, gasreq: BigNumber, id: BigNumber} - this is sent when a bid or ask offer is added to the book (or updated)
  • OfferFail with key fields: ba:'asks'|'bids', olKeyHash:string, taker:string, id: BigNumber, takerWants:BigNumber, takerGives:BigNumber, penalty:BigNumber, mgvData:string} - this is sent when an offer with id: id failed to deliver. Note that mgvData is a bytes32 string encoding of the failure reason recorded by Mangrove.
  • OfferSuccess with key fields: olKeyHash: string, taker: string, id: BigNumber, takerWants:Big, takerGives:Big} - this is sent when the offer with id: id was successfully executed (possibly on a partial fill whenever offer.gives>takerWants).

There are more events - see BookSubscriptionEvent for the reference for events emitted by a Mangrove market.