Add ERC20 L0 how-to

docs/build/isc/v1.1/docs/how-tos/send-ERC20-across-chains.md

@@ -0,0 +1,297 @@
+# Send ERC20 Tokens Across Chains
+
+## Introduction
+
+[LayerZero OFT V2](https://docs.layerzero.network/v2) enables cross-chain transfers of existing ERC20 tokens, such as wSMR and wIOTA (wrapped versions of the native gas tokens SMR and IOTA on ShimmerEVM and IOTA EVM respectively). For testing purposes, Sepolia is chosen as the source chain, while the BNB Testnet is chosen as the destination chain.
+
+:::info Community Libs
+
+You can clone the Utilities for LayerZero OFT V2 from [IOTA Community GitHub Repository](https://github.com/iota-community/layerzero-oft-v2-utils).
+
+:::
+
+### Why Would a User Need to Send ERC20 Tokens Across Chains?
+
+Sending ERC20 tokens across chains allows users to leverage different blockchain networks' strengths and unique features, optimize costs, and manage risks more effectively. This flexibility is crucial as the blockchain ecosystem continues to grow and diversify.
+
+#### Send Existing ERC20 Tokens Across Chains
+
+You need both the [OFT Adapter](https://docs.layerzero.network/v2/developers/evm/oft/adapter) and OFT contracts to enable existing ERC20 tokens for cross-chain sending,
+
+#### Create New Cross-chain Fungible Tokens
+
+If you are about to launch a new ERC20 token, you can use the [OFT standard](https://docs.layerzero.network/v2/developers/evm/oft/quickstart)  to enable cross-chain sending without the OFT Adapter.
+
+## How To Use IOTA's Utilities for LayerZero OFT V2
+
+The [Utilities for LayerZero OFT V2](https://github.com/iota-community/layerzero-oft-v2-utils) facilitate cross-chain sending of ERC20 tokens between a source chain (e.g., Sepolia or ShimmerEVM Testnet) and a destination chain (e.g., BNB Testnet or IOTA EVM Testnet).
+
+:::tip Further Information
+
+You can learn more about the available options in the [Layer Zero Documentation](https://docs.layerzero.network/v2/developers/evm/gas-settings/options#option-types.).
+
+:::
+
+### Send Tokens From One Source Chain to Another Destination Chain (and Vice Versa)
+
+To send existing ERC20 tokens, you will need both the OFT Adapter contract on the source chain and the OFT contract on the destination chain. You should then use the following procedure:
+
+#### 1. Approve the tokens
+
+The sender must approve their ERC20 tokens for the OFT Adapter contract.
+
+```typescript 
+const approveTx = await erc20TokenContract.approve(oftAdapterContractAddress, amountInWei);
+```
+
+#### 2. Estimate the fee
+
+The sender calls the function `quoteSend()` of the OFT Adapter contract to estimate the cross-chain fee to be paid in native tokens on the source chain.
+
+```typescript
+ const sendParam = [
+    lzEndpointIdOnDestChain,
+    receiverAddressInBytes32,
+    amountInWei,
+    amountInWei,
+    options, // additional options
+    "0x", // composed message for the send() operation
+    "0x", // OFT command to be executed, unused in default OFT implementations
+  ];
+
+  // https://github.com/LayerZero-Labs/LayerZero-v2/blob/main/oapp/contracts/oft/interfaces/IOFT.sol#L127C60-L127C73
+  // false is set for _payInLzToken Flag indicating whether the caller is paying in the LZ token
+  const [nativeFee] = await myOFTAdapterContract.quoteSend(sendParam as any, false);
+```
+
+#### 3. Send the tokens
+
+The sender calls the function `send()` of the OFT Adapter contract to transfer tokens from the source chain to the destination chain.
+
+```typescript
+  const sendTx = await myOFTAdapterContract.send(
+    sendParam as any,
+    [nativeFee, 0] as any, // set 0 for lzTokenFee
+    sender.address, // refund address
+    {
+      value: nativeFee,
+    },
+  );
+  const sendTxReceipt = await sendTx.wait();
+  console.log("sendOFT - send tx on source chain:", sendTxReceipt?.hash);
+```
+
+#### 4. (Optional) Wait for Finalization
+
+The sender can wait for transaction finalization on the destination chain using the library [@layerzerolabs/scan-client](https://www.npmjs.com/package/@layerzerolabs/scan-client#example-usage).
+```typescript
+  const deliveredMsg = await waitForMessageReceived(
+    Number(lzEndpointIdOnDestChain),
+    sendTxReceipt?.hash as string,
+  );
+  console.log("sendOFT - received tx on destination chain:", deliveredMsg?.dstTxHash);
+```
+
+### Send the OFT-wrapped Tokens Back
+
+To send back the OFT-wrapped tokens on the destination chain to the source chain, the procedure is similar, except that the approval step is not needed:
+
+#### 1. Estimate the fee
+
+The sender calls the function `quoteSend()` of the OFT contract to estimate the cross-chain fee to be paid in native tokens on the sender chain.
+
+```typescript
+ // Set the send param
+  // https://github.com/LayerZero-Labs/LayerZero-v2/blob/main/oapp/contracts/oft/interfaces/IOFT.sol#L10
+  const sendParam = [
+    lzEndpointIdOnSrcChain, // Sepolia
+    receiverAddressInBytes32,
+    amountInWei,
+    amountInWei,
+    options, // additional options
+    "0x", // composed message for the send() operation
+    "0x", // OFT command to be executed, unused in default OFT implementations
+  ];
+
+  // Step 1: call the func quoteSend() to estimate cross-chain fee to be paid in native on the source chain
+  // https://github.com/LayerZero-Labs/LayerZero-v2/blob/main/oapp/contracts/oft/interfaces/IOFT.sol#L127C60-L127C73
+  // false is set for _payInLzToken Flag indicating whether the caller is paying in the LZ token
+  const [nativeFee] = await myOFTContract.quoteSend(sendParam as any, false);
+  console.log("sendOFTBack - estimated nativeFee:", ethers.formatEther(nativeFee));
+  ```
+
+#### 2. Send the tokens
+
+The sender calls the function `send()` of the OFT contract to transfer tokens from the destination chain back to the source chain.
+
+```typescript
+const sendTx = await myOFTContract.send(
+    sendParam as any,
+    [nativeFee, 0] as any, // set 0 for lzTokenFee
+    sender.address, // refund address
+    {
+      value: nativeFee,
+    },
+  );
+  const sendTxReceipt = await sendTx.wait();
+  console.log("sendOFTBack - send tx on source chain:", sendTxReceipt?.hash);
+  ```
+
+#### 3. (Optional) Wait for Finalization
+
+The sender can wait for transaction finalization on the destination chain using the library `@layerzerolabs/scan-client`.
+```typescript
+ const deliveredMsg = await waitForMessageReceived(
+    Number(lzEndpointIdOnDestChain),
+    sendTxReceipt?.hash as string,
+  );
+  console.log("sendOFTBack - received tx on destination chain:", deliveredMsg?.dstTxHash);
+  ```
+
+## Sample Solidity Code for OFT Adapter and OFT Contracts in the `contracts-standard` Folder
+
+The [contracts-standard](https://github.com/iota-community/layerzero-oft-v2-utils/tree/main/contracts-standard) contains scripts to:
+
+- [Deploy the OFT Adapter and OFT contracts](#deploy-the-oft-adapter-contract-on-the-source-chain).
+- [Set your trusted peers](#optional-set-the-trusted-peers).
+- Set enforced options.
+- [Send tokens from the source chain to the destination chain](#send-the-origin-tokens-from-the-source-chain-to-the-destination-chain),
+and [vice versa](#send-oft-wrapped-tokens-back-from-the-destination-chain-to-the-origin-chain).
+
+### Install the Library
+
+After you have cloned the [IOTA Community Utilities for LayerZero OFT V2 repository](https://github.com/iota-community/layerzero-oft-v2-utils/tree/main), you should run the following command to install:
+
+```
+yarn
+```
+
+### Compile the Contracts
+
+If you want to use the standard implementation for ERC20, copy the [`contracts-standard`](https://github.com/iota-community/layerzero-oft-v2-utils/tree/main/contracts-standard) folder to `contracts`. If you want to use a custom implementation, copy the  [`contracts-wiota`](https://github.com/iota-community/layerzero-oft-v2-utils/tree/main/contracts-wiota) to `contracts`. Then, run the following command to compile the contracts:
+
+```bash
+yarn compile
+``` 
+
+### Set Your Configuration
+
+You should copy the template [`.env.example`](https://github.com/iota-community/layerzero-oft-v2-utils/blob/main/.env.example) file to a file called `.env`, and edit any of the configuration options you see fit.
+
+```bash
+cp .env.example .env
+```
+
+### Deploy the Contracts
+
+#### Deploy the OFT Adapter Contract On the Source Chain
+
+The OFT Adapter facilitates the expansion of an existing token to any supported blockchain as a native token, maintaining a unified global supply and inheriting all features of the OFT Standard. This intermediary contract manages the sending and receiving of pre-deployed tokens.
+
+For instance, when an ERC20 token is transferred from the source chain (Chain A), it gets locked in the OFT Adapter. Consequently, a corresponding token is minted on the destination chain (Chain B) through the paired OFT Contract.
+
+```bash
+yarn deploy-oft-adapter-sepolia
+```
+
+Expected log output :
+
+```bash
+npx hardhat run scripts/deploy_oft_adapter.ts --network sepolia
+Deployed MyOFTAdapter contract address: 0x4daa81978576cB91a2e1919960e90e46c2a6D586
+Done in 6.67s.
+```
+
+#### Deploy OFT on the Destination Chain
+
+You can use the following command to deploy OFT on destination chain (e.g. BNB Testnet):
+
+```bash
+yarn deploy-oft-bnb-testnet
+``` 
+
+Expected log output :
+
+```bash
+npx hardhat run scripts/deploy_oft.ts --network bnbTestnet
+Deployed MyOFT contract address: 0xCc337C2e69F4Eb8EaBcf632a1fC5B8F729dC47F1
+Done in 6.68s.
+```
+
+### (optional) Set the Trusted Peers
+
+#### On OFTAdapter
+
+You can set the trusted peer in the source chain's OFT Adapter (e.g., Sepolia) using the following command:
+
+```bash
+yarn set-peer-oft-adapter-sepolia
+```
+
+Expected log output :
+
+```bash
+npx hardhat run scripts/set_peer_oft_adapter.ts --network sepolia
+setPeerMyOFTAdapter - oftAdapterContractAddress:0x4daa81978576cB91a2e1919960e90e46c2a6D586, lzEndpointIdOnDestChain:40102, oftContractAddress:0xCc337C2e69F4Eb8EaBcf632a1fC5B8F729dC47F1
+MyOFTAdapter - setPeer tx: 0xc17e7a54d96325768b6427ce893d9b6b7ed04bd920089b63a3f96c005073e9c2
+Done in 14.10s.
+```
+
+#### On OFT
+
+You can add a trusted peer in the destination chain (e.g. BNB Testnet) using the following command:
+
+```bash
+yarn set-peer-oft-bnb-testnet
+```
+
+Expected log output :
+
+```bash
+npx hardhat run scripts/set_peer_oft.ts --network bnbTestnet
+setPeerMyOFT - oftContractAddress:0xCc337C2e69F4Eb8EaBcf632a1fC5B8F729dC47F1, lzEndpointIdOnSrcChain:40161, oftAdapterContractAddress:0x4daa81978576cB91a2e1919960e90e46c2a6D586
+MyOFT - setPeer tx: 0xb0012378ee14c9df5c9f86980dd9c96fc8aedb3c19d92c1d91a4259f3981ac35
+Done in 4.66s.
+```
+
+### Send the Origin Tokens from the Source Chain to the Destination Chain
+
+
+You can use the following command to send tokens from the source chain to the destination chain:
+
+```bash
+yarn send-oft-from-sepolia
+```
+
+Expected log output :
+
+```bash
+npx hardhat run scripts/send_oft.ts --network sepolia
+sendOFT - oftAdapterContractAddress:0x5D7Cbc05fc6df2832c40023f1Eb2755628C51D81, oftContractAddress:0x075e512E25b45a3EaF8b432220F0Ca8D4e3c6a58, lzEndpointIdOnSrcChain:40161, lzEndpointIdOnDestChain:40102, gasDropInWeiOnDestChain:1000000000000000, executorLzReceiveOptionMaxGas:200000, receivingAccountAddress:0x5e812d3128D8fD7CEac08CEca1Cd879E76a6E028, sender: 0x57a4bd139fb673d364a6f12df9177a3f686625f3, amount:2
+sendOFT - approve tx: 0x8fa692edb47b1ad9d21f60b0fa30993e5cd3abd78c3c56fb4f38db5f9b8ac369
+sendOFT - estimated nativeFee: 0.000734209489447653
+sendOFT - send tx on source chain: 0xeb3e44310a09ae2ab2f0d6d6d3fdfd7c490f8ac536bb20a5e16999b23232ef67
+Wait for cross-chain tx finalization by LayerZero ...
+sendOFT - received tx on destination chain: 0xc2e5a4be8ae67718e817ff585a32765e393835880068f408fd7724667a25a46c
+```
+
+### Send Oft-Wrapped Tokens Back From the Destination Chain to the Origin Chain
+
+You can use the following command to send the OFT-wrapped tokens back to the origin chain:
+
+
+```bash
+yarn send-oft-back-from-bnb-testnet
+```
+
+Expected log output :
+
+```bash
+npx hardhat run scripts/send_oft_back.ts --network bnbTestnet
+sendOFTBack - oftAdapterContractAddress:0x5D7Cbc05fc6df2832c40023f1Eb2755628C51D81, oftContractAddress:0x075e512E25b45a3EaF8b432220F0Ca8D4e3c6a58, lzEndpointIdOnSrcChain:40161, lzEndpointIdOnDestChain:40102, gasDropInWeiOnDestChain:1000000000000000, executorLzReceiveOptionMaxGas:200000, receivingAccountAddress:0x57A4bD139Fb673D364A6f12Df9177A3f686625F3, sender: 0x5e812d3128D8fD7CEac08CEca1Cd879E76a6E028, amount:2
+sendOFTBack - estimated nativeFee: 0.054815809525020364
+sendOFTBack - send tx on source chain: 0x41bcf78b310dc1bbf9b4005f7412d995011c7815ad5af9cc26b37370e75bbfeb
+Wait for cross-chain tx finalization by LayerZero ...
+sendOFTBack - received tx on destination chain: 0xc1031694e92512a0189885ad6419e33196a65b8ae56baa9d555be8686d6d42fe
+```
+

docs/build/isc/v1.1/sidebars.js

@@ -84,6 +84,11 @@ module.exports = {
           label: 'Create Custom Tokens - ERC20',
           id: 'how-tos/ERC20',
         },
+        {
+          type: 'doc',
+          label: 'Send ERC20 Tokens Across Chains',
+          id: 'how-tos/send-ERC20-across-chains',
+        },
         {
           type: 'doc',
           label: 'Create NFTs - ERC721',