useSignTransaction

Composable to sign a Solana transaction using the connected wallet from Web3Auth.

Import

import { useSignTransaction } from '@web3auth/modal/vue/solana'

Usage

<script setup lang="ts">
  import { ref } from 'vue'
  import { useSignTransaction } from '@web3auth/modal/vue/solana'
  import type { Transaction } from '@solana/kit'

  const transaction = ref<Transaction | null>(null) // Your transaction object
  const { signTransaction, loading, error, data } = useSignTransaction()

  const handleSign = async () => {
    if (!transaction.value) return
    try {
      await signTransaction(transaction.value)
      // Do something with data.value (signed transaction)
    } catch (e) {
      // Handle error
    }
  }
</script>

<template>
  <div>
    <button @click="handleSign" :disabled="loading">
      {{ loading ? "Signing..." : "Sign Transaction" }}
    </button>
    <div v-if="error">Error: {{ error.message }}</div>
    <div v-if="data">Signed Transaction: {{ data }}</div>
  </div>
</template>

Return type

export type IUseSignTransaction = {
  loading: Ref<boolean>
  error: Ref<Web3AuthError | null>
  data: Ref<string | null>
  signTransaction: (transaction: TransactionOrVersionedTransaction) => Promise<string>
}

loading

Ref<boolean>

Indicates if the transaction signing is in progress.

error

Ref<Web3AuthError | null>

Error object if signing fails, otherwise null.

data

Ref<string | null>

The signed transaction as a string, or null if not signed yet.

signTransaction

(transaction: TransactionOrVersionedTransaction) => Promise<string>

Function to sign a Solana transaction. Returns the signed transaction as a string.

Example

SignTransaction.vue

<script setup lang="ts">
  import { ref } from 'vue'
  import { useWeb3Auth } from '@web3auth/modal/vue'
  import { useSolanaWallet, useSignTransaction } from '@web3auth/modal/vue/solana'

  import { buildSolTransferTransaction } from '../solana/transfer'

  const { web3Auth } = useWeb3Auth()
  const { accounts } = useSolanaWallet()
  const {
    data: signedTransaction,
    error,
    loading: isPending,
    signTransaction,
  } = useSignTransaction()
  const formError = ref<string | null>(null)

  async function submit(event: Event) {
    event.preventDefault()
    formError.value = null

    const rpcTarget = web3Auth.value?.currentChain?.rpcTarget
    if (!rpcTarget || !accounts.value?.length) return

    const form = new FormData(event.target as HTMLFormElement)
    const to = form.get('address')?.toString().trim() ?? ''
    const amountSol = Number(form.get('value'))
    if (!to || !Number.isFinite(amountSol) || amountSol <= 0) {
      formError.value = 'Enter a valid recipient address and a positive amount.'
      return
    }

    try {
      const transaction = await buildSolTransferTransaction(
        rpcTarget,
        accounts.value[0],
        to,
        amountSol
      )
      await signTransaction(transaction)
    } catch (err) {
      formError.value = err instanceof Error ? err.message : 'Failed to sign transaction.'
    }
  }
</script>

<template>
  <div>
    <h2>Sign Transaction</h2>
    <form @submit.prevent="submit">
      <input name="address" placeholder="Recipient address" required />
      <input name="value" placeholder="Amount (SOL)" type="number" step="0.01" min="0" required />
      <button type="submit" :disabled="isPending">
        {{ isPending ? 'Signing...' : 'Sign' }}
      </button>
    </form>
    <div v-if="signedTransaction" class="hash">Signed transaction: {{ signedTransaction }}</div>
    <div v-if="formError ?? error?.message" class="error">
      Error: {{ formError ?? error?.message }}
    </div>
  </div>
</template>

solana/transfer.ts

import type { Transaction } from '@solana/kit'
import {
  address,
  appendTransactionMessageInstruction,
  compileTransaction,
  createNoopSigner,
  createSolanaRpc,
  createTransactionMessage,
  lamports,
  pipe,
  setTransactionMessageFeePayerSigner,
  setTransactionMessageLifetimeUsingBlockhash,
} from '@solana/kit'
import { getTransferSolInstruction } from '@solana-program/system'

export async function buildSolTransferTransaction(
  rpcTarget: string,
  from: string,
  to: string,
  amountSol: number
): Promise<Transaction> {
  const rpc = createSolanaRpc(rpcTarget)
  const { value: latestBlockhash } = await rpc.getLatestBlockhash().send()
  const feePayer = createNoopSigner(address(from))

  const message = pipe(
    createTransactionMessage({ version: 0 }),
    m => setTransactionMessageFeePayerSigner(feePayer, m),
    m => setTransactionMessageLifetimeUsingBlockhash(latestBlockhash, m),
    m =>
      appendTransactionMessageInstruction(
        getTransferSolInstruction({
          source: feePayer,
          destination: address(to),
          amount: lamports(BigInt(Math.round(amountSol * 1e9))),
        }),
        m
      )
  )

  return compileTransaction(message)
}