feat(sdk): add approval fns to the SDK

.changeset/thin-seahorses-fry.md

+---
+'@eth-optimism/sdk': patch
+---
+
+Add approval functions to the SDK

packages/sdk/src/adapters/eth-bridge.ts

 /* eslint-disable @typescript-eslint/no-unused-vars */
-import { ethers, Overrides } from 'ethers'
+import { ethers, Contract, Overrides, BigNumber } from 'ethers'
 import { TransactionRequest, BlockTag } from '@ethersproject/abstract-provider'
-import { predeploys } from '@eth-optimism/contracts'
+import { predeploys, getContractInterface } from '@eth-optimism/contracts'
 import { hexStringEquals } from '@eth-optimism/core-utils'
 
 import {
@@ -17,6 +17,14 @@ import { StandardBridgeAdapter } from './standard-bridge'
  * Bridge adapter for the ETH bridge.
  */
 export class ETHBridgeAdapter extends StandardBridgeAdapter {
+  public async approval(
+    l1Token: AddressLike,
+    l2Token: AddressLike,
+    signer: ethers.Signer
+  ): Promise<BigNumber> {
+    throw new Error(`approval not necessary for ETH bridge`)
+  }
+
   public async getDepositsByAddress(
     address: AddressLike,
     opts?: {
@@ -104,6 +112,17 @@ export class ETHBridgeAdapter extends StandardBridgeAdapter {
   }
 
   populateTransaction = {
+    approve: async (
+      l1Token: AddressLike,
+      l2Token: AddressLike,
+      amount: NumberLike,
+      opts?: {
+        overrides?: Overrides
+      }
+    ): Promise<TransactionRequest> => {
+      throw new Error(`approvals not necessary for ETH bridge`)
+    },
+
     deposit: async (
       l1Token: AddressLike,
       l2Token: AddressLike,

packages/sdk/src/adapters/standard-bridge.ts

@@ -185,6 +185,38 @@ export class StandardBridgeAdapter implements IBridgeAdapter {
     }
   }
 
+  public async approval(
+    l1Token: AddressLike,
+    l2Token: AddressLike,
+    signer: ethers.Signer
+  ): Promise<BigNumber> {
+    if (!(await this.supportsTokenPair(l1Token, l2Token))) {
+      throw new Error(`token pair not supported by bridge`)
+    }
+
+    const token = new Contract(
+      toAddress(l1Token),
+      getContractInterface('L2StandardERC20'), // Any ERC20 will do
+      this.messenger.l1Provider
+    )
+
+    return token.allowance(await signer.getAddress(), this.l1Bridge.address)
+  }
+
+  public async approve(
+    l1Token: AddressLike,
+    l2Token: AddressLike,
+    amount: NumberLike,
+    signer: Signer,
+    opts?: {
+      overrides?: Overrides
+    }
+  ): Promise<TransactionResponse> {
+    return signer.sendTransaction(
+      await this.populateTransaction.approve(l1Token, l2Token, amount, opts)
+    )
+  }
+
   public async deposit(
     l1Token: AddressLike,
     l2Token: AddressLike,
@@ -217,6 +249,31 @@ export class StandardBridgeAdapter implements IBridgeAdapter {
   }
 
   populateTransaction = {
+    approve: async (
+      l1Token: AddressLike,
+      l2Token: AddressLike,
+      amount: NumberLike,
+      opts?: {
+        overrides?: Overrides
+      }
+    ): Promise<TransactionRequest> => {
+      if (!(await this.supportsTokenPair(l1Token, l2Token))) {
+        throw new Error(`token pair not supported by bridge`)
+      }
+
+      const token = new Contract(
+        toAddress(l1Token),
+        getContractInterface('L2StandardERC20'), // Any ERC20 will do
+        this.messenger.l1Provider
+      )
+
+      return token.populateTransaction.approve(
+        this.l1Bridge.address,
+        amount,
+        opts?.overrides || {}
+      )
+    },
+
     deposit: async (
       l1Token: AddressLike,
       l2Token: AddressLike,
@@ -288,6 +345,19 @@ export class StandardBridgeAdapter implements IBridgeAdapter {
   }
 
   estimateGas = {
+    approve: async (
+      l1Token: AddressLike,
+      l2Token: AddressLike,
+      amount: NumberLike,
+      opts?: {
+        overrides?: Overrides
+      }
+    ): Promise<BigNumber> => {
+      return this.messenger.l1Provider.estimateGas(
+        await this.populateTransaction.approve(l1Token, l2Token, amount, opts)
+      )
+    },
+
     deposit: async (
       l1Token: AddressLike,
       l2Token: AddressLike,

packages/sdk/src/cross-chain-messenger.ts

@@ -109,7 +109,7 @@ export class CrossChainMessenger implements ICrossChainMessenger {
     if (Provider.isProvider(this.l1SignerOrProvider)) {
       return this.l1SignerOrProvider
     } else {
-      return this.l1SignerOrProvider.provider
+      return this.l1SignerOrProvider.provider as any
     }
   }
 
@@ -117,7 +117,7 @@ export class CrossChainMessenger implements ICrossChainMessenger {
     if (Provider.isProvider(this.l2SignerOrProvider)) {
       return this.l2SignerOrProvider
     } else {
-      return this.l2SignerOrProvider.provider
+      return this.l2SignerOrProvider.provider as any
     }
   }
 
@@ -844,6 +844,36 @@ export class CrossChainMessenger implements ICrossChainMessenger {
     )
   }
 
+  public async approval(
+    l1Token: AddressLike,
+    l2Token: AddressLike,
+    opts?: {
+      signer?: Signer
+    }
+  ): Promise<BigNumber> {
+    const bridge = await this.getBridgeForTokenPair(l1Token, l2Token)
+    return bridge.approval(l1Token, l2Token, opts?.signer || this.l1Signer)
+  }
+
+  public async approveERC20(
+    l1Token: AddressLike,
+    l2Token: AddressLike,
+    amount: NumberLike,
+    opts?: {
+      signer?: Signer
+      overrides?: Overrides
+    }
+  ): Promise<TransactionResponse> {
+    return (opts?.signer || this.l1Signer).sendTransaction(
+      await this.populateTransaction.approveERC20(
+        l1Token,
+        l2Token,
+        amount,
+        opts
+      )
+    )
+  }
+
   public async depositERC20(
     l1Token: AddressLike,
     l2Token: AddressLike,
@@ -986,6 +1016,18 @@ export class CrossChainMessenger implements ICrossChainMessenger {
       )
     },
 
+    approveERC20: async (
+      l1Token: AddressLike,
+      l2Token: AddressLike,
+      amount: NumberLike,
+      opts?: {
+        overrides?: Overrides
+      }
+    ): Promise<TransactionRequest> => {
+      const bridge = await this.getBridgeForTokenPair(l1Token, l2Token)
+      return bridge.populateTransaction.approve(l1Token, l2Token, amount, opts)
+    },
+
     depositERC20: async (
       l1Token: AddressLike,
       l2Token: AddressLike,
@@ -1082,6 +1124,24 @@ export class CrossChainMessenger implements ICrossChainMessenger {
       )
     },
 
+    approveERC20: async (
+      l1Token: AddressLike,
+      l2Token: AddressLike,
+      amount: NumberLike,
+      opts?: {
+        overrides?: Overrides
+      }
+    ): Promise<BigNumber> => {
+      return this.l1Provider.estimateGas(
+        await this.populateTransaction.approveERC20(
+          l1Token,
+          l2Token,
+          amount,
+          opts
+        )
+      )
+    },
+
     depositERC20: async (
       l1Token: AddressLike,
       l2Token: AddressLike,

packages/sdk/src/interfaces/bridge-adapter.ts

@@ -78,6 +78,41 @@ export interface IBridgeAdapter {
     l2Token: AddressLike
   ): Promise<boolean>
 
+  /**
+   * Queries the account's approval amount for a given L1 token.
+   *
+   * @param l1Token The L1 token address.
+   * @param l2Token The L2 token address.
+   * @param signer Signer to query the approval for.
+   * @returns Amount of tokens approved for deposits from the account.
+   */
+  approval(
+    l1Token: AddressLike,
+    l2Token: AddressLike,
+    signer: Signer
+  ): Promise<BigNumber>
+
+  /**
+   * Approves a deposit into the L2 chain.
+   *
+   * @param l1Token The L1 token address.
+   * @param l2Token The L2 token address.
+   * @param amount Amount of the token to approve.
+   * @param signer Signer used to sign and send the transaction.
+   * @param opts Additional options.
+   * @param opts.overrides Optional transaction overrides.
+   * @returns Transaction response for the approval transaction.
+   */
+  approve(
+    l1Token: AddressLike,
+    l2Token: AddressLike,
+    amount: NumberLike,
+    signer: Signer,
+    opts?: {
+      overrides?: Overrides
+    }
+  ): Promise<TransactionResponse>
+
   /**
    * Deposits some tokens into the L2 chain.
    *
@@ -131,6 +166,25 @@ export interface IBridgeAdapter {
    * Follows the pattern used by ethers.js.
    */
   populateTransaction: {
+    /**
+     * Generates a transaction for approving some tokens to deposit into the L2 chain.
+     *
+     * @param l1Token The L1 token address.
+     * @param l2Token The L2 token address.
+     * @param amount Amount of the token to approve.
+     * @param opts Additional options.
+     * @param opts.overrides Optional transaction overrides.
+     * @returns Transaction that can be signed and executed to deposit the tokens.
+     */
+    approve(
+      l1Token: AddressLike,
+      l2Token: AddressLike,
+      amount: NumberLike,
+      opts?: {
+        overrides?: Overrides
+      }
+    ): Promise<TransactionRequest>
+
     /**
      * Generates a transaction for depositing some tokens into the L2 chain.
      *
@@ -181,6 +235,25 @@ export interface IBridgeAdapter {
    * Follows the pattern used by ethers.js.
    */
   estimateGas: {
+    /**
+     * Estimates gas required to approve some tokens to deposit into the L2 chain.
+     *
+     * @param l1Token The L1 token address.
+     * @param l2Token The L2 token address.
+     * @param amount Amount of the token to approve.
+     * @param opts Additional options.
+     * @param opts.overrides Optional transaction overrides.
+     * @returns Gas estimate for the transaction.
+     */
+    approve(
+      l1Token: AddressLike,
+      l2Token: AddressLike,
+      amount: NumberLike,
+      opts?: {
+        overrides?: Overrides
+      }
+    ): Promise<BigNumber>
+
     /**
      * Estimates gas required to deposit some tokens into the L2 chain.
      *

packages/sdk/src/interfaces/cross-chain-messenger.ts

@@ -411,6 +411,44 @@ export interface ICrossChainMessenger {
     }
   ): Promise<TransactionResponse>
 
+  /**
+   * Queries the account's approval amount for a given L1 token.
+   *
+   * @param l1Token The L1 token address.
+   * @param l2Token The L2 token address.
+   * @param opts Additional options.
+   * @param opts.signer Optional signer to get the approval for.
+   * @returns Amount of tokens approved for deposits from the account.
+   */
+  approval(
+    l1Token: AddressLike,
+    l2Token: AddressLike,
+    opts?: {
+      signer?: Signer
+    }
+  ): Promise<BigNumber>
+
+  /**
+   * Approves a deposit into the L2 chain.
+   *
+   * @param l1Token The L1 token address.
+   * @param l2Token The L2 token address.
+   * @param amount Amount of the token to approve.
+   * @param opts Additional options.
+   * @param opts.signer Optional signer to use to send the transaction.
+   * @param opts.overrides Optional transaction overrides.
+   * @returns Transaction response for the approval transaction.
+   */
+  approveERC20(
+    l1Token: AddressLike,
+    l2Token: AddressLike,
+    amount: NumberLike,
+    opts?: {
+      signer?: Signer
+      overrides?: Overrides
+    }
+  ): Promise<TransactionResponse>
+
   /**
    * Deposits some ERC20 tokens into the L2 chain.
    *
@@ -517,6 +555,25 @@ export interface ICrossChainMessenger {
       }
     ): Promise<TransactionRequest>
 
+    /**
+     * Generates a transaction for approving some tokens to deposit into the L2 chain.
+     *
+     * @param l1Token The L1 token address.
+     * @param l2Token The L2 token address.
+     * @param amount Amount of the token to approve.
+     * @param opts Additional options.
+     * @param opts.overrides Optional transaction overrides.
+     * @returns Transaction response for the approval transaction.
+     */
+    approveERC20(
+      l1Token: AddressLike,
+      l2Token: AddressLike,
+      amount: NumberLike,
+      opts?: {
+        overrides?: Overrides
+      }
+    ): Promise<TransactionRequest>
+
     /**
      * Generates a transaction for depositing some ETH into the L2 chain.
      *
@@ -652,6 +709,25 @@ export interface ICrossChainMessenger {
       }
     ): Promise<BigNumber>
 
+    /**
+     * Estimates gas required to approve some tokens to deposit into the L2 chain.
+     *
+     * @param l1Token The L1 token address.
+     * @param l2Token The L2 token address.
+     * @param amount Amount of the token to approve.
+     * @param opts Additional options.
+     * @param opts.overrides Optional transaction overrides.
+     * @returns Transaction response for the approval transaction.
+     */
+    approveERC20(
+      l1Token: AddressLike,
+      l2Token: AddressLike,
+      amount: NumberLike,
+      opts?: {
+        overrides?: Overrides
+      }
+    ): Promise<BigNumber>
+
     /**
      * Estimates gas required to deposit some ETH into the L2 chain.
      *