indexing-blocks

name	indexing-blocks
description	Use when processing every block (or every Nth block) for time-series data, periodic snapshots, or block-level aggregations. indexer.onBlock API, where filter with block-number range and stride, and block handler context.

Block Handlers

Process every block (or every Nth block) using indexer.onBlock. No contract address or config.yaml entry needed.

Handler

Branch by chain.id with a switch so the type system flags any unconfigured chain via the default: never exhaustiveness check:

import { indexer } from "generated";

indexer.onBlock(
  {
    name: "BlockTracker",
    where: ({ chain }) => {
      switch (chain.id) {
        case 1:
          return { block: { number: { _gte: 18000000, _every: 100 } } };
        case 8453:
          return { block: { number: { _every: 50 } } };
        default: {
          // Exhaustiveness check: TypeScript errors here if a new chain ID
          // is added to config.yaml but not handled above.
          const _exhaustive: never = chain.id;
          return false;
        }
      }
    },
  },
  async ({ block, context }) => {
    context.BlockSnapshot.set({
      id: `${block.number}`,
      blockNumber: BigInt(block.number),
    });
  }
);

Options

Option	Type	Required	Description
name	string	yes	Handler name for logging
where	({ chain }) => boolean | filter	no	Predicate evaluated once per configured chain at registration. Return false to skip a chain, true / omit to match every block, or {block: {number: {_gte?, _lte?, _every?}}} to restrict range and stride. _every aligns relative to _gte, preserving (blockNumber - _gte) % _every === 0.

Other ecosystems

• Fuel: same indexer.onBlock API; filter is keyed by block.height instead of block.number.
• SVM: use indexer.onSlot; filter shape is {slot: {_gte?, _lte?, _every?}} and the handler arg is {slot: number, context} (no block wrapper).

Notes

• indexer.onBlock self-registers — no config.yaml entry needed
• No events or contract address required
• The handler context has the same entity API as event handlers
• If where returns false for every configured chain, a warning is logged at registration time
• For per-event startBlock (not stride), use indexer.onEvent with where.block.number._gte (see indexing-filters). Event filters accept _gte only; _lte/_every are reserved for onBlock.

Deep Documentation

Full reference: https://docs.envio.dev/docs/HyperIndex-LLM/hyperindex-complete