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read-blocks.md

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Read Blocks

A block is a change to the blockchain storage with a batch of changes that happen simultaneously. With VeChain, every ~10s a new block is generated, even if no transaction has been published.

The most relevant information for interacting with Blocks includes:

  • number: the number of the block
  • id: a unique id representing the block
  • parentID: the previous block the block is based on
  • timestamp: the unix time at which the block was stored
  • isFinalized: is the block securely finalized in a snapshot
  • transactions: contain either all transaction ids or full transaction details including receipts

There are two methods to obtain block details:

  1. The compressed version, which includes all data and only the transaction IDs.
  2. The expanded version, which also encompasses full transaction details along with the generated outputs.

A block can be requested as number, id and additionally the reserved words "best" and "finalized" reference the latest or epoch ending blocks.

const blockNumber = 12345678;

// get the block and transaction ids within it
const compressed = await thor.blocks.getBlockCompressed(blockNumber);
console.log(compressed);

// get the block and transaction data including receipts
const expanded = await thor.blocks.getBlockExpanded(blockNumber);
console.log(expanded);

Test it yourself:

{% embed url="https://stackblitz.com/github/vechain-energy/example-snippets/tree/v1.0.0/sdk/read-block?ctl=1&embed=1&file=index.mjs&hideExplorer=1&hideNavigation=1&view=editor" %}

Type definition and documentation of all attributes:

The same information is available using the JSON-API:

Special Blocks

There are specific keywords associated with special blocks:

  • Genesis refers to the initial block (number 0) on a chain, serving to identify the available chain on a network.
  • Best represents the most recent block, typically having a maximum age of 10 seconds, as a new block is added every 10 seconds.
  • Final denotes the most recent finalized block, marking the end of an epoch. It is guaranteed that there will be no further re-ordering or changes. A checkpoint happens every 180 blocks and finalization of a checkpointed block occurs again after 180 blocks.