Installation

npm install eamutils --save

Description

This package will be used for some util functions I reuse in many projects.

Strings

- truncate(str: string, maxLength: number, suffix: string)
- truncateMiddle(str: string, maxLength: number, suffix: string)

Numbers

- formatNumberToK(num: number, precision: number = 1, replaces: string[] = ['K', 'M', 'B', 'T'])
- formatNumberCommas(num: any)
- padLeadingZeros(num: any, finalLength: number)

Web3

- getAddresses(text: string) -> Returns a list of addresses detected in a given string
- address(addr: string) -> Returns checksumed address

Providers

There is a list of some common routes and providers.

1. ETH Mainnet
5. Goerli
56. Binance Smart Chain
97. Binance Smart Chain Testnet

You can add your own provider by using the following method:

Provider.createProvider(provider: IProvider)

The IProvider definition is the following (only chainId and rpc are required)

export interface IProvider {
    chainId: number,
    rpcs: string[],

    // Optional data
    name?: string,
    explorer?: string,
    router?: string,
    factory?: string,
    factory_abi?: string,
    router_abi?: string,
    multicall?: string
};

So, to add Arbitrum for example, we should do something like this:

const provider = Provider.createProvider({
    chainId: 42161,
    rpcs: [
        'https://arbitrum.blockpi.network/v1/rpc/public'
    ]
})

Routers and factory contracts

So, to get a router or factory contract from a custom provider, we should specific factory and router parameters (with the addresses of each one).

• To get a router, you can do something like this:

const provider = Provider.getProviderByChainId(1);
const router = Contract.getRouterFromProvider(provider);
const factory = await router.factory();
console.log(`Factory address: ${factory}`);

• To get a factory, you can do this:

const provider = Provider.getProviderByChainId(1);
const factory = Contract.getFactoryFromProvider(provider);

• To get a custom contract instance, you can do this:

const provider = web3Utils.Provider.getProviderByChainId(1);
const contract = web3Utils.Contract.getContractFromAddress(provider, SC_CUSTOM_ADDRESS, SC_CUSTOM_ABI);

Tokens

• To get a token contract instance, you can do this:

const provider = web3Utils.Provider.getProviderByChainId(1);
const token = web3Utils.Token.getContract(provider, '0x811beEd0119b4AfCE20D2583EB608C6F7AF1954f');

• Now you can fetch the price for a token, given a provider and two addresses

This method will fetch the price based on a baseToken and quoteToken

const provider = web3Utils.Provider.getProviderByChainId(56);
const wbnb = '0xbb4cdb9cbd36b01bd1cbaebf2de08d9173bc095c';
const usdt = '0x55d398326f99059ff775485246999027b3197955';
const amountWBNB = 1;
const price = web3Utils.Token.getPrice(provider, wbnb, usdt, amountWBNB);

// Returns the amount of usdt needed to swap for a WBNB.

• Also, you can fetch the price given a path

const provider = web3Utils.Provider.getProviderByChainId(56);
const wbnb = '0xbb4cdb9cbd36b01bd1cbaebf2de08d9173bc095c';
const usdt = '0x55d398326f99059ff775485246999027b3197955';
const amountWBNB = 1;
const price = web3Utils.Token.getPriceUsingPath(provider, [wbnb, usdt], amountWBNB);

// Returns the amount of usdt needed to swap for a WBNB.