feat: prepareAuthorization (#3062)

* feat: add `prepareAuthorization`

* chore: format

* Update rotten-camels-knock.md

* chore: up snapshots

.changeset/rotten-camels-knock.md

@@ -0,0 +1,5 @@
+---
+"viem": patch
+---
+
+**Experimental (EIP-7702):** Added `prepareAuthorization`.

site/pages/experimental/eip7702/prepareAuthorization.md

@@ -0,0 +1,179 @@
+---
+description: Prepares an EIP-7702 Authorization for signing.
+---
+
+# prepareAuthorization
+
+Prepares an [EIP-7702 Authorization](https://eips.ethereum.org/EIPS/eip-7702) for signing. 
+This Action will fill the required fields of the Authorization object if they are not provided (e.g. `nonce` and `chainId`).
+
+With the prepared Authorization object, you can use [`signAuthorization`](/experimental/eip7702/signAuthorization) to sign over it.
+
+## Usage
+
+:::code-group
+
+```ts twoslash [example.ts]
+import { walletClient } from './client'
+
+const authorization = await walletClient.prepareAuthorization({ // [!code focus]
+  contractAddress: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2', // [!code focus]
+}) // [!code focus]
+// @log: {
+// @log:   chainId: 1,
+// @log:   contractAddress: "0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2",
+// @log:   nonce: 1,
+// @log: }
+
+const signedAuthorization = await walletClient.signAuthorization(authorization)
+```
+
+```ts twoslash [client.ts] filename="client.ts"
+import { createWalletClient, http } from 'viem'
+import { privateKeyToAccount } from 'viem/accounts'
+import { mainnet } from 'viem/chains'
+import { eip7702Actions } from 'viem/experimental'
+
+export const walletClient = createWalletClient({
+  account: privateKeyToAccount('0x...'),
+  chain: mainnet,
+  transport: http(),
+}).extend(eip7702Actions())
+```
+
+:::
+
+### Explicit Scoping
+
+We can explicitly set a `nonce` and/or `chainId` by supplying them as parameters:
+
+:::code-group
+
+```ts twoslash [example.ts]
+import { walletClient } from './client'
+
+const authorization = await walletClient.prepareAuthorization({
+  contractAddress: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
+  chainId: 10, // [!code focus]
+})
+// @log: {
+// @log:   chainId: 10,
+// @log:   contractAddress: "0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2",
+// @log:   nonce: 420,
+// @log: }
+
+const signedAuthorization = await walletClient.signAuthorization(authorization)
+```
+
+```ts twoslash [client.ts] filename="client.ts"
+import { createWalletClient, http } from 'viem'
+import { privateKeyToAccount } from 'viem/accounts'
+import { mainnet } from 'viem/chains'
+import { eip7702Actions } from 'viem/experimental'
+
+export const walletClient = createWalletClient({
+  account: privateKeyToAccount('0x...'),
+  chain: mainnet,
+  transport: http(),
+}).extend(eip7702Actions())
+```
+
+:::
+
+## Returns
+
+`Authorization`
+
+A prepared & unsigned Authorization object.
+
+## Parameters
+
+### account
+
+- **Type:** `Account`
+
+Account to use to prepare the Authorization object. 
+
+Accepts a [Local Account (Private Key, etc)](/docs/clients/wallet#local-accounts-private-key-mnemonic-etc).
+
+```ts twoslash
+import { privateKeyToAccount } from 'viem/accounts'
+import { walletClient } from './client'
+
+const authorization = await walletClient.prepareAuthorization({
+  account: privateKeyToAccount('0x...'), // [!code focus]
+  contractAddress: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2'
+}) 
+```
+
+### chainId (optional)
+
+- **Type:** `Address`
+- **Default:** `client.chain.id` or Network chain ID
+
+The Chain ID to scope the Authorization to. If set to zero (`0`), then the Authorization will
+be valid on all chains.
+
+```ts twoslash
+import { privateKeyToAccount } from 'viem/accounts'
+import { walletClient } from './client'
+
+const authorization = await walletClient.prepareAuthorization({
+  account: privateKeyToAccount('0x...'),
+  contractAddress: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
+  chainId: 1, // [!code focus]
+}) 
+```
+
+### contractAddress
+
+- **Type:** `Address`
+
+The target Contract to designate onto the Account.
+
+```ts twoslash
+import { privateKeyToAccount } from 'viem/accounts'
+import { walletClient } from './client'
+
+const authorization = await walletClient.prepareAuthorization({
+  account: privateKeyToAccount('0x...'),
+  contractAddress: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2' // [!code focus]
+}) 
+```
+
+### delegate (optional)
+
+- **Type:** `true | Address | Account`
+
+Whether the EIP-7702 Transaction will be executed by another Account.
+
+If not specified, it will be assumed that the EIP-7702 Transaction will be executed by the Account that signed the Authorization.
+
+```ts twoslash
+import { privateKeyToAccount } from 'viem/accounts'
+import { walletClient } from './client'
+
+const authorization = await walletClient.prepareAuthorization({
+  account: privateKeyToAccount('0x...'),
+  contractAddress: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
+  delegate: true, // [!code focus]
+}) 
+```
+
+### nonce (optional)
+
+- **Type:** `Address`
+- **Default:** Account's next available nonce.
+
+The nonce to scope the Authorization to.
+
+```ts twoslash
+import { privateKeyToAccount } from 'viem/accounts'
+import { walletClient } from './client'
+
+const authorization = await walletClient.prepareAuthorization({
+  account: privateKeyToAccount('0x...'),
+  contractAddress: '0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2',
+  nonce: 69, // [!code focus]
+}) 
+```

site/sidebar.ts

@@ -1301,6 +1301,10 @@ export const sidebar = {
           {
             text: 'Actions',
             items: [
+              {
+                text: 'prepareAuthorization',
+                link: '/experimental/eip7702/prepareAuthorization',
+              },
               {
                 text: 'signAuthorization',
                 link: '/experimental/eip7702/signAuthorization',

src/experimental/eip7702/actions/prepareAuthorization.test.ts

@@ -0,0 +1,174 @@
+import { beforeAll, expect, test } from 'vitest'
+import { wagmiContractConfig } from '../../../../test/src/abis.js'
+import { anvilMainnet } from '../../../../test/src/anvil.js'
+import { accounts } from '../../../../test/src/constants.js'
+import { privateKeyToAccount } from '../../../accounts/privateKeyToAccount.js'
+import { reset } from '../../../actions/index.js'
+import { prepareAuthorization } from './prepareAuthorization.js'
+
+const account = privateKeyToAccount(accounts[0].privateKey)
+const client = anvilMainnet.getClient()
+
+beforeAll(async () => {
+  await reset(client, {
+    blockNumber: anvilMainnet.forkBlockNumber,
+    jsonRpcUrl: anvilMainnet.forkUrl,
+  })
+})
+
+test('default', async () => {
+  const authorization = await prepareAuthorization(client, {
+    account,
+    contractAddress: wagmiContractConfig.address,
+    chainId: 1,
+    nonce: 0,
+  })
+
+  expect(authorization).toMatchInlineSnapshot(
+    `
+    {
+      "chainId": 1,
+      "contractAddress": "0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2",
+      "nonce": 0,
+    }
+  `,
+  )
+})
+
+test('behavior: partial authorization: no chainId + nonce', async () => {
+  const authorization = await prepareAuthorization(client, {
+    account,
+    contractAddress: wagmiContractConfig.address,
+  })
+
+  expect(authorization).toMatchInlineSnapshot(
+    `
+    {
+      "chainId": 1,
+      "contractAddress": "0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2",
+      "nonce": 664,
+    }
+  `,
+  )
+})
+
+test('behavior: partial authorization: no nonce', async () => {
+  const authorization = await prepareAuthorization(client, {
+    account,
+    contractAddress: wagmiContractConfig.address,
+    chainId: 10,
+  })
+
+  expect(authorization).toMatchInlineSnapshot(
+    `
+    {
+      "chainId": 10,
+      "contractAddress": "0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2",
+      "nonce": 664,
+    }
+  `,
+  )
+})
+
+test('behavior: partial authorization: no chainId', async () => {
+  const authorization = await prepareAuthorization(client, {
+    account,
+    contractAddress: wagmiContractConfig.address,
+    nonce: 69,
+  })
+
+  expect(authorization).toMatchInlineSnapshot(
+    `
+    {
+      "chainId": 1,
+      "contractAddress": "0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2",
+      "nonce": 69,
+    }
+  `,
+  )
+})
+
+test('behavior: delegate is address', async () => {
+  const authorization = await prepareAuthorization(client, {
+    account,
+    contractAddress: wagmiContractConfig.address,
+    delegate: '0x0000000000000000000000000000000000000000',
+  })
+
+  expect(authorization.nonce).toBe(663)
+})
+
+test('behavior: delegate is truthy', async () => {
+  const authorization = await prepareAuthorization(client, {
+    account,
+    contractAddress: wagmiContractConfig.address,
+    delegate: true,
+  })
+
+  expect(authorization.nonce).toBe(663)
+})
+
+test('behavior: account as delegate', async () => {
+  const authorization = await prepareAuthorization(client, {
+    account,
+    contractAddress: wagmiContractConfig.address,
+    delegate: account,
+  })
+
+  expect(authorization.nonce).toBe(664)
+})
+
+test('behavior: hoisted account on client', async () => {
+  const client = anvilMainnet.getClient({ account })
+  const authorization = await prepareAuthorization(client, {
+    contractAddress: wagmiContractConfig.address,
+    chainId: 1,
+    nonce: 0,
+  })
+
+  expect(authorization).toMatchInlineSnapshot(
+    `
+    {
+      "chainId": 1,
+      "contractAddress": "0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2",
+      "nonce": 0,
+    }
+  `,
+  )
+})
+
+test('behavior: no client chain', async () => {
+  const client = anvilMainnet.getClient({ chain: false })
+  const authorization = await prepareAuthorization(client, {
+    account,
+    contractAddress: wagmiContractConfig.address,
+    nonce: 0,
+  })
+
+  expect(authorization).toMatchInlineSnapshot(
+    `
+    {
+      "chainId": 1,
+      "contractAddress": "0xFBA3912Ca04dd458c843e2EE08967fC04f3579c2",
+      "nonce": 0,
+    }
+  `,
+  )
+})
+
+test('error: no account', async () => {
+  await expect(() =>
+    // @ts-expect-error
+    prepareAuthorization(client, {
+      contractAddress: wagmiContractConfig.address,
+      chainId: 1,
+      nonce: 0,
+    }),
+  ).rejects.toThrowErrorMatchingInlineSnapshot(`
+    [AccountNotFoundError: Could not find an Account to execute with this Action.
+    Please provide an Account with the \`account\` argument on the Action, or by supplying an \`account\` to the Client.
+
+    Docs: https://viem.sh/experimental/eip7702/prepareAuthorization
+    Version: viem@x.y.z]
+  `)
+})