CosmWasmJS#

This article focuses on how to use CosmoWasmJS for connectiong to OKTC nodes and interacting with smart contracts. CosmWasmJS is an SDK that facilitates contract development for DApp developers. Combined with CosmJS, you can easily and conveniently develop OKTC Wasm smart contracts.

CosmWasmJS + CosmJS is equivalent to ETH's web3.js.

Note: If you want a more detailed explanation of CosmWasmJS and wasm smart contract interactions, please refer to CosmWasmJS

Preconditions#

Need to install Node while using CosmoWasmJS

Choice of network#

You can choose between mainnet or local testnet.

Cosmwasm on mainnet is coming soon. Use local testnet instead for now.

Mainnet#

There is no need to build nodes on the main network, and the development of OKTC wasm contracts can directly access the RPC node services provided by OKTC. If you need to build your own mainnet node, please refer to mainnet node set up.

Below is the URL of the mainnet RPC node

const rpcEndpoint = "https://exchaintmrpc.okex.org"

Install Node.js#

https://nodejs.org/en/download/

Create project#

Note: everything in this subsection uses local testnet

Create project directory

# use an empty directory
mkdir cosmwasmjs && cd cosmwasmjs

Install the dependencies

# install the dependencies
npm install cosmwasm
npm install @cosmjs/crypto

Create a code file

# create an emtpy file to write code
touch client.mjs

Compile JS code#

Note: everything in this subsection uses local testnet

Copy the following codes into client.mjs

import { SigningCosmWasmClient, Secp256k1HdWallet, coin, parseCoins } from "cosmwasm";
import { stringToPath } from "@cosmjs/crypto";

// This is your rpc endpoint
// If you choice mainnet ,please use "https://exchaintmrpc.okex.org"
const rpcEndpoint = "http://localhost:26657";

// Using mnemonic
// You must change mnemonic if you use your mnemonic
const mnemonic = "palace cube bitter light woman side pave cereal donor bronze twice work";

async function main() {
// Create a wallet
const path = stringToPath("m/44'/118'/0'/0/0");
const wallet = await Secp256k1HdWallet.fromMnemonic(mnemonic, {hdPaths:[path], "prefix":"ex"});
const accs = await wallet.getAccounts();

    // Create Wasm Client
    const client = await SigningCosmWasmClient.connectWithSigner(
        rpcEndpoint,
        wallet,
    );
    const balance = await client.getBalance(accs[0].address,'okt')
    console.log("------------------------------------------------------------------------------------")
    console.log("SigningCosmWasmClient CONNECTION Success")
    console.log("account:",accs[0].address);
    console.log("balance:",balance);
    
    // Query Wasm all code 
    const codes = await client.getCodes();
    console.log("------------------------------------------------------------------------------------")
    console.log("Query all Wasm code:")
    console.log(codes);
}

main();

Run code#

Note: everything in this subsection uses local testnet

Next, run code

node client.mjs

Contract interaction interface#

The above only shows how to connect OKTC nodes through CosmWasmJS, the actions for querying account balances and all wasm contract code operations. If you want to conduct other smart contract actions, you can refer to the interfaces in the table below for uploading contract codes, deploying contracts and interacting with contracts.

Notes

CosmWasmClient : this client is only used for querying

SigningCosmWasmClient : this client is used for sending transactions

Example#

We provide a Webpack demo example. You can follow this example to interact with OKTC through your browser and Keplr wallet using CosmWasmJS and Webpack. And we also provide another demo example. You can create evm compatible address with oks.js.