How to access Koinos Blockchain Network with Node.js

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Koinos is made to be accessible to developers and users. With just a few lines of code, we can interact with the blockchain.

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Getting Started

Learn to Use Terminal

Install NPM/Node.js

Install Git

Clone this repo

git clone https://github.com/isaacdozier/learn-koinos.git
cd learn-koinos

How to Clone a Repository

Install Dependencies

npm install @koindx/v2-sdk

The Basics of Dependencies for Node.js & NPM

Now open a terminal and run the command below.

Terminal

node example_4.js

Example #4 outputs USDT/Koin pair data.

Output

Pair {
  chain: 'EiBZK_GGVP0H_fXVAM3j6EAuz3-B-l3ejxRSewi7qIBfSA==',
  address: '16PVFQ6bwRnAZD7i3xmu6jX6MoG3vwYYgW',
  provider: Provider {
    rpcNodes: [ 'https://api.koinos.io' ],
    currentNodeId: 0,
    onError: [Function (anonymous)]
  },
  klast: BigNumber { s: 1, e: 25, c: [ 766121720972, 45537572324692 ] },
  block_time: BigNumber { s: 1, e: 12, c: [ 1711789576980 ] },
  token_0: Token {
    chainId: 'EiBZK_GGVP0H_fXVAM3j6EAuz3-B-l3ejxRSewi7qIBfSA==',
    address: '19WrWze3XAoMa3Mwqys4rJMP6emZX2wfpH',
    decimals: undefined,
    symbol: undefined,
    name: undefined,
    isNative: false,
    isToken: true
  },
  token_1: KOIN {
    chainId: 'EiBZK_GGVP0H_fXVAM3j6EAuz3-B-l3ejxRSewi7qIBfSA==',
    address: 'koin',
    decimals: 8,
    symbol: 'KOIN',
    name: 'Koin',
    isNative: true,
    isToken: false
  },
  reserve_0: BigNumber { s: 1, e: 12, c: [ 8638433253253 ] },
  reserve_1: BigNumber { s: 1, e: 12, c: [ 8895397946881 ] },
  total_supply: BigNumber { s: 1, e: 12, c: [ 8544172553644 ] }
}

Run More Examples

Example_6.js : returns Koin & USDT Pool Reserves and estimates the exchange rate by calculating pool impact.

const { ChainId, Token, Fetcher, KOIN } = require("@koindx/v2-sdk")
const BigNumber = require("bignumber.js")

// usdt dollar qty in
const udst_dollars_in = 100

// Convert usdt to BigNumber Object
const asset = new BigNumber(udst_dollars_in * 100000000)

// Koindx fee is needed for estimating exchange rate [ 0.25% ]
const koindx_fee = new BigNumber(1 - 0.0025)

go(asset)

async function go(asset_in){
    try{

        // DECLARE ASSETS
        // KOIN can be declared directly with Koindx sdk
        const koin = new KOIN(ChainId.MAINNET)

        // USDT is NOT a native asset and is declared using the Token class
        // This same operation would be used for other alt-tokens in the ecosystem
        const usdt_contract_address = '19WrWze3XAoMa3Mwqys4rJMP6emZX2wfpH'
        const usdt = new Token(ChainId.MAINNET, usdt_contract_address)

        // This retrieves the Koin/USDT pool data by utilizing the Koindx SDK
        const PAIR = await Fetcher.fetchPairData(ChainId.MAINNET, koin, usdt)

        // Lets declare our availible reserves to get the pool ratio
        // This can be used to get an estimated exchange rate for any given pool
        let rsv_0 = PAIR.reserve_0
        let rsv_1 = PAIR.reserve_1

        // Calculate margin impact of asset-in - [ apply koindx fee = 0.25% ]
        let impact = rsv_1.dividedBy(rsv_1.plus(asset_in * koindx_fee))

        // Calculate margin impact of asset-out
        let est = rsv_0.minus(rsv_0.times(impact))

        console.log(est)
        

    } catch (error) {
        console.error(error)
    }
}

Find more Koindx V2-SDK Examples

Working with Numbers

BigNumber.js is a mathmatic standard used for working with a wide range of numbers, strings and object types representing a numeric value.

If you want to create or manipulate them in you app, you'll need to include the dependency below.

const BigNumber = require('bignumber.js');

This makes working with numbers easier for developers.

Learn how to work with BigNumber.js

Arithmic functions with numbers and strings

console.log(koin_reserves * 1)

Output: 8810421275766

console.log(koin_reserves * '1')

Output: 8810421275766

Operation methods

let operation = a.plus(b)
                a.minus(b)
                a.dividedBy(b)
                a.times(b)

If you liked this guide, check out the step by step process to install a Kondor wallet to interact with the network.

How to Create a Kondor Wallet

Support Me

If you are feeling extra generous you can donate to my Koinos wallet directly. Any of the handles below can be used in the Kondor wallet to send assets in-network without fees. Mana is used instead which charges over time. Network costs are an opportunity cost measured with time.

KAP Domain: gucci.koin

Nickname: @gucci

Public Address: 15tagV4TF6AawesDrWNmzsTp64wWr1oQet