Cosmos blockchainのTypeScript client, CosmJSの紹介

CosmJS

CosmJSが公式のJSのクライアントツールっぽい。
https://github.com/cosmos/cosmjs

チュートリアル

このチュートリアルを見れば基本的な使い方がわかる。
https://tutorials.cosmos.network/tutorials/7-cosmjs/2-first-steps.html

たとえばテストネットでトークンをfaucetして、sendするコードはこんな感じ。

import { readFile } from "fs/promises"
import { DirectSecp256k1HdWallet, OfflineDirectSigner } from "@cosmjs/proto-signing"
import { IndexedTx, SigningStargateClient, StargateClient } from "@cosmjs/stargate"
import { MsgSend } from "cosmjs-types/cosmos/bank/v1beta1/tx"
import { Tx } from "cosmjs-types/cosmos/tx/v1beta1/tx"

const rpc = "https://rpc.sentry-01.theta-testnet.polypore.xyz"

const getAliceSignerFromMnemonic = async (): Promise<OfflineDirectSigner> => {
    return DirectSecp256k1HdWallet.fromMnemonic((await readFile("./testnet.alice.mnemonic.key")).toString(), {
        prefix: "cosmos",
    })
}

const runAll = async (): Promise<void> => {
    const client = await StargateClient.connect(rpc)
    console.log("With client, chain id:", await client.getChainId(), ", height:", await client.getHeight())
    console.log(
        "Alice balances:",
        await client.getAllBalances("cosmos17tvd4hcszq7lcxuwzrqkepuau9fye3dal606zf")
    )
    const faucetTx: IndexedTx = (await client.getTx(
        "540484BDD342702F196F84C2FD42D63FA77F74B26A8D7383FAA5AB46E4114A9B"
    ))!
    console.log("Faucet Tx:", faucetTx)
    const decodedTx: Tx = Tx.decode(faucetTx.tx)
    console.log("DecodedTx:", decodedTx)
    console.log("Decoded messages:", decodedTx.body!.messages)
    const sendMessage: MsgSend = MsgSend.decode(decodedTx.body!.messages[0].value)
    console.log("Sent message:", sendMessage)
    const faucet: string = sendMessage.fromAddress
    console.log("Faucet balances:", await client.getAllBalances(faucet))

    // Get the faucet address another way
    {
        const rawLog = JSON.parse(faucetTx.rawLog)
        console.log("Raw log:", JSON.stringify(rawLog, null, 4))
        const faucet: string = rawLog[0].events
            .find((eventEl: any) => eventEl.type === "coin_spent")
            .attributes.find((attribute: any) => attribute.key === "spender").value
        console.log("Faucet address from raw log:", faucet)
    }

    const aliceSigner: OfflineDirectSigner = await getAliceSignerFromMnemonic()
    const alice = (await aliceSigner.getAccounts())[0].address
    console.log("Alice's address from signer", alice)
    const signingClient = await SigningStargateClient.connectWithSigner(rpc, aliceSigner)
    console.log(
        "With signing client, chain id:",
        await signingClient.getChainId(),
        ", height:",
        await signingClient.getHeight()
    )

    console.log("Gas fee:", decodedTx.authInfo!.fee!.amount)
    console.log("Gas limit:", decodedTx.authInfo!.fee!.gasLimit.toString(10))
    console.log("Alice balance before:", await client.getAllBalances(alice))
    console.log("Faucet balance before:", await client.getAllBalances(faucet))
    const result = await signingClient.sendTokens(alice, faucet, [{ denom: "uatom", amount: "100000" }], {
        amount: [{ denom: "uatom", amount: "500" }],
        gas: "200000",
    })
    console.log("Transfer result:", result)
    console.log("Alice balance after:", await client.getAllBalances(alice))
    console.log("Faucet balance after:", await client.getAllBalances(faucet))
}

runAll()

ほかにもローカルノードでsend tokenする方法や、private keyからwallet generateする方法などものってる。

結論

typescript client toolは公式のCosmJSを使っておけば大丈夫。