The Graph - `subgraph.yaml`
```yaml
specVersion: 0.0.4
description: Uniswap is a decentralized protocol for automated token exchange on Ethereum.
repository: https://github.com/Uniswap/v4-subgraph
schema:
file: ./schema.graphql
features:
- nonFatalErrors
- grafting
- kind: ethereum/contract
name: PositionManager
network: mainnet
source:
abi: PositionManager
address: "0xbD216513d74C8cf14cf4747E6AaA6420FF64ee9e"
startBlock: 21689089
mapping:
kind: ethereum/events
apiVersion: 0.0.7
language: wasm/assemblyscript
file: ./src/mappings/index.ts
entities:
- Position
abis:
- name: PositionManager
file: ./abis/PositionManager.json
eventHandlers:
- event: Subscription(indexed uint256,indexed address)
handler: handleSubscription
- event: Unsubscription(indexed uint256,indexed address)
handler: handleUnsubscription
- event: Transfer(indexed address,indexed address,indexed uint256)
handler: handleTransfer
```
HyperIndex - `config.yaml`
```yaml
# yaml-language-server: $schema=./node_modules/envio/evm.schema.json
name: uni-v4-indexer
chains:
- id: 1
start_block: 21689089
contracts:
- name: PositionManager
address: "0xbD216513d74C8cf14cf4747E6AaA6420FF64ee9e"
events:
- event: Subscription(uint256 indexed tokenId, address indexed subscriber)
- event: Unsubscription(uint256 indexed tokenId, address indexed subscriber)
- event: Transfer(address indexed from, address indexed to, uint256 indexed id)
```
If you hit any issues, check the [Configuration File](https://docs.envio.dev/docs/HyperIndex/configuration-file) docs or reach out to our team in [Discord](https://discord.gg/envio).
### schema.graphql Migration
This step is simple. You keep the entire file as is, with one small change: remove all `@entity` directives from your entities. Everything else stays the same.
### Event Handler Migration
This is the final step of the migration which consists of two parts:
- Moving from AssemblyScript to TypeScript
- Updating Subgraph syntax to HyperIndex syntax
#### AssemblyScript to TypeScript
HyperIndex uses TypeScript instead of AssemblyScript. Since AssemblyScript is a subset of TypeScript, you can simply copy most of your code over without worrying about major syntax changes.
#### Subgraph to HyperIndex
The HyperIndex workflow is very similar to Subgraphs, but there are a few important differences to keep in mind:
- Replace `ENTITY.save()` with `context.ENTITY.set(VALUES)`
- Handlers need to be async
- Use `await` when loading entities
As you start using HyperIndex, you’ll pick up the differences quickly.
Here is a code snippet to give you a sense of what these changes look like in practice.
The Graph - `eventHandler.ts`
```typescript
export function handleSubscription(event: SubscriptionEvent): void {
const subscription = new Subscribe(event.transaction.hash + event.logIndex);
subscription.tokenId = event.params.tokenId;
subscription.address = event.params.subscriber.toHexString();
subscription.logIndex = event.logIndex;
subscription.blockNumber = event.block.number;
subscription.position = event.params.tokenId;
subscription.save();
}
```
HyperIndex - `eventHandler.ts`
```typescript
import { indexer } from "envio";
indexer.onEvent(
{ contract: "PoolManager", event: "Subscription" },
async ({ event, context }) => {
const entity = {
id: event.transaction.hash + event.logIndex,
tokenId: event.params.tokenId,
address: event.params.subscriber,
blockNumber: event.block.number,
logIndex: event.logIndex,
position: event.params.tokenId,
};
context.Subscription.set(entity);
},
);
```
For a few extra tips on migrating from Alchemy to Envio, check out our other [migration guide](https://docs.envio.dev/docs/HyperIndex/migration-guide#extra-tips) in our docs.
## Share Your Learnings
If you come across anything useful during your migration, please feel free to contribute. Simply open a [PR](https://github.com/enviodev/docs/pulls) to this guide and help future developers.
## Getting Help
Join our [Discord](https://discord.gg/envio) if you need support. It is the fastest way to get direct help from the team and the community.