Indexer Factory

Factory / Dynamic Contracts

For contracts created at runtime by factory contracts (e.g., Uniswap Pair creation).

Config

Dynamic contracts have no address — they're registered by contractRegister:

contracts:
  - name: Factory
    events:
      - event: PairCreated(indexed address token0, indexed address token1, address pair, uint256)
  - name: Pair
    # No address — registered dynamically
    events:
      - event: Swap(indexed address sender, uint256 amount0In, ...)
      - event: Sync(uint112 reserve0, uint112 reserve1)

chains:
  - id: 1
    contracts:
      - name: Factory
        address:
          - 0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f
      - name: Pair
        # No address here — will be registered by contractRegister

contractRegister

Register new contract addresses for indexing with indexer.contractRegister. The event handler is a separate indexer.onEvent registration — order and file placement between the two don't matter:

import { indexer, type Pair } from "envio";

indexer.contractRegister(
  { contract: "Factory", event: "PairCreated" },
  async ({ event, context }) => {
    context.chain.Pair.add(event.params.pair);
  },
);

indexer.onEvent(
  { contract: "Factory", event: "PairCreated" },
  async ({ event, context }) => {
    const pair: Pair = {
      id: event.params.pair,
      token0_id: event.params.token0,
      token1_id: event.params.token1,
    };
    context.Pair.set(pair);
  },
);

context.chain.<ContractName>.add(address) is available for every contract in config that has no address. The <ContractName> matches the contract name in config.yaml.

Async Contract Register

Perform external calls to decide which contract to register:

indexer.contractRegister(
  { contract: "NftFactory", event: "SimpleNftCreated" },
  async ({ event, context }) => {
    const version = await getContractVersion(event.params.contractAddress);
    if (version === "v2") {
      context.chain.SimpleNftV2.add(event.params.contractAddress);
    } else {
      context.chain.SimpleNft.add(event.params.contractAddress);
    }
  },
);

Same-Block Coverage

When a dynamic contract is registered, the Envio Indexer indexes all events from that contract in the same block where it was created — even events from earlier transactions in that block.

If something is unclear, use the envio-docs skill to search and read the latest documentation.