meshjs-cardano

• Building Cardano dApps with MeshJS (TypeScript/JavaScript)
• Integrating CIP-30 wallet connectors
• Transaction building in browser or Node.js

• Confirm MeshJS version and environment (Next.js, Vite, Node)
• Never request seed phrases or private keys
• Handle wallet disconnects gracefully
• Test on preprod before mainnet

Installation

```bash

npm install @meshsdk/core @meshsdk/react

# or

yarn add @meshsdk/core @meshsdk/react

```

Provider setup

```typescript

import { BlockfrostProvider } from '@meshsdk/core';

const provider = new BlockfrostProvider('');

// or for preprod:

const provider = new BlockfrostProvider('', 'preprod');

```

```tsx

import { CardanoWallet, useWallet } from '@meshsdk/react';

function App() {

const { connected, wallet } = useWallet();

return (

);

}

```

Simple ADA transfer

```typescript

import { Transaction } from '@meshsdk/core';

const tx = new Transaction({ initiator: wallet })

.sendLovelace(

'addr_test1qz...',

'5000000' // 5 ADA

);

const unsignedTx = await tx.build();

const signedTx = await wallet.signTx(unsignedTx);

const txHash = await wallet.submitTx(signedTx);

```

With native tokens

```typescript

const tx = new Transaction({ initiator: wallet })

.sendAssets(

'addr_test1qz...',

[

{ unit: 'lovelace', quantity: '2000000' },

{ unit: '', quantity: '1' }

]

);

```

With metadata

```typescript

const tx = new Transaction({ initiator: wallet })

.sendLovelace('addr_test1qz...', '1000000')

.setMetadata(674, { msg: ['Hello from MeshJS'] });

```

Lock funds at script

```typescript

import { Data } from '@meshsdk/core';

const datum: Data = {

alternative: 0,

fields: [wallet.getPaymentAddress()]

};

const tx = new Transaction({ initiator: wallet })

.sendLovelace(

{

address: scriptAddress,

datum: { inline: datum }

},

'5000000'

);

```

Spend from script

```typescript

const tx = new Transaction({ initiator: wallet })

.redeemValue({

value: scriptUtxo,

script: plutusScript,

datum: datum,

redeemer: { data: { alternative: 0, fields: [] } }

})

.sendLovelace(recipientAddress, '4500000')

.setCollateral([collateralUtxo]);

```

Example: NFT minting

User request: "Mint an NFT with MeshJS"

Response:

```typescript

import { ForgeScript, Transaction } from '@meshsdk/core';

// Create minting script (time-locked)

const { pubKeyHash } = wallet.getPaymentAddress();

const forgingScript = ForgeScript.withOneSignature(pubKeyHash);

const assetMetadata = {

name: 'My NFT',

image: 'ipfs://...',

mediaType: 'image/png'

};

const tx = new Transaction({ initiator: wallet })

.mintAsset(

forgingScript,

{

assetName: 'MyNFT',

assetQuantity: '1',

metadata: assetMetadata,

label: '721',

recipient: wallet.getPaymentAddress()

}

);

const unsignedTx = await tx.build();

const signedTx = await wallet.signTx(unsignedTx);

const txHash = await wallet.submitTx(signedTx);

console.log('Minted:', txHash);

```

Example: Query UTxOs

```typescript

import { BlockfrostProvider } from '@meshsdk/core';

const provider = new BlockfrostProvider('');

// Get UTxOs for address

const utxos = await provider.fetchAddressUTxOs(address);

// Get UTxOs at script address

const scriptUtxos = await provider.fetchAddressUTxOs(scriptAddress);

// Filter by asset

const nftUtxos = utxos.filter(utxo =>

utxo.output.amount.some(a => a.unit.includes(policyId))

);

```

Error handling

```typescript

try {

const txHash = await wallet.submitTx(signedTx);

console.log('Success:', txHash);

} catch (error) {

if (error.message.includes('UTxO')) {

console.log('UTxO issue - refresh and retry');

} else if (error.message.includes('collateral')) {

console.log('Need ADA-only UTxO for collateral');

}

}

```

Wallet state management

```typescript

const { connected, connecting, disconnect, wallet, name } = useWallet();

// Check connection before operations

if (!connected) {

throw new Error('Wallet not connected');

}

// Get network

const network = await wallet.getNetworkId();

// 0 = testnet, 1 = mainnet

```

• Never request seed phrases
• Validate CIP-30 API availability
• Handle disconnects gracefully
• Show confirmation before signing

• shared/PRINCIPLES.md
• [MeshJS documentation](https://meshjs.dev)
• [CIP-30 Wallet API](https://cips.cardano.org/cips/cip30/)