# NEAR Lake Primitive Types This crate contains the primitive types used by the [NEAR Lake Framework package](https://www.npmjs.com/package/@near-lake/framework). These types are used to define the data structures used by the framework as well as provide some popular helper functions. ## Types ### `Block` #### `Block` Structure Definition The `Block` type is used to represent a block in the NEAR Lake Framework. It is comprised by the following structure: ```ts export class Block { constructor( readonly streamerMessage: StreamerMessage, private executedReceipts: Receipt[], readonly postponedReceipts: Receipt[], readonly transactions: Transaction[], private _actions: Map, private _events: Map, private _stateChanges: StateChange[]) { } ... // helper methods and getters ommitted for brevity } ``` ##### `streamerMessage` Low-level structure for backward compatibility. As implemented in previous versions of [`near-lake-framework`](https://www.npmjs.com/package/near-lake-framework). ##### `postponedReceipts` Receipts included on the chain but not executed yet marked as “postponed”: they are represented by the same structure `Receipt` (see the corresponding section in this doc for more details). ##### `transactions` List of included `Transactions`, converted into `Receipts`. **_NOTE_:** Heads up! You might want to know about `Transactions` to know where the action chain has begun. Unlike Ethereum, where a Transaction contains everything you may want to know about a particular interaction on the Ethereum blockchain, Near Protocol because of its asynchronous nature converts a `Transaction` into a `Receipt` before executing it. Thus, On NEAR, `Receipts` are more important for figuring out what happened on-chain as a result of a Transaction signed by a user. Read more about [Transactions on Near](https://nomicon.io/RuntimeSpec/Transactions) here. #### `Block` Helper Methods ```ts export class Block { ... // constructor ommitted for brevity get blockHash(): string {} get prevBlockHash(): string {} get blockHeight(): number {} header(): BlockHeader {} receipts(): Receipt[] {} actions(): Action[] {} events(): Event[] {} stateChanges(): StateChange[] {} actionByReceiptId(receipt_id: string): Action | undefined {} eventsByReceiptId(receipt_id: string): Event[] {} eventsByAccountId(account_id: string): Event[] {} private buildActionsHashmap() {} private buildEventsHashmap(): Map {} static fromStreamerMessage(streamerMessage: StreamerMessage): Block {} } ``` ##### `blockHash` Returns the block hash. A shortcut to get the data from the block header. ##### `prevBlockHash` Returns the previous block hash. A shortcut to get the data from the block header. ##### `blockHeight` Returns the block height. A shortcut to get the data from the block header. ##### `header(): BlockHeader` Returns a `BlockHeader` structure of the block See `BlockHeader` structure sections for details. ##### `receipts(): Receipt[]` Returns a slice of `Receipts` executed in the block. Basically is a getter for the `executedReceipts` field. ##### `actions(): Action[]` Returns an Array of `Actions` executed in the block. ##### `events(): Event[]` Returns `Events` emitted in the block. ##### `stateChanges(): StateChange[]` Returns an Array of `StateChange` occurred in the block. ##### `actionByReceiptId(receipt_id: string): Action | undefined` Returns `Action`s of the provided `receipt_id` from the block if any. Returns `undefined` if there is no corresponding `Action`. This method uses the internal `Block` `action` field which is empty by default and will be filled with the block’s actions on the first call to optimize memory usage. The result is either `Action | undefined` since there might be a request for an `Action` by `receipt_id` from another block, in which case this method will be unable to find the `Action` in the current block. In the other case, the request might be for an `Action` for a `receipt_id` that belongs to a `DataReceipt` where an action does not exist. ##### `eventsByReceiptId(receipt_id: string): Event[]` Returns an Array of Events emitted by `ExecutionOutcome` for the given `receipt_id`. There might be more than one `Event` for the `Receipt` or there might be none of them. In the latter case, this method returns an empty Array. ##### `eventsByAccountId(account_id: string): Event[]` Returns an Array of Events emitted by `ExecutionOutcome` for the given `account_id`. There might be more than one `Event` for the `Receipt` or there might be none of them. In the latter case, this method returns an empty Array. ### Important Notes on `Block` - All the entities located on different shards were merged into one single list without differentiation. - `Block` is not the fairest name for this structure either. NEAR Protocol is a sharded blockchain, so its block is actually an ephemeral structure that represents a collection of real blocks called chunks in NEAR Protocol. ### `BlockHeader` Replacement for `BlockHeaderView` from `near-primitives`. Shrunken and simplified. Note: the original `BlockHeaderView` is still accessible via the `.streamerMessage` attribute. #### `BlockHeader` Structure Definition ```ts export class BlockHeader { constructor( readonly height: number, readonly hash: string, readonly prevHash: string, readonly author: string, readonly timestampNanosec: string, readonly epochId: string, readonly nextEpochId: string, readonly gasPrice: string, readonly totalSupply: string, readonly latestProtocolVersion: number, readonly randomValue: string, readonly chunksIncluded: number, readonly validatorProposals: ValidatorStakeView[]) { } ... // helper method ommitted for brevity } ``` ### `Receipt` This field is a simplified representation of the `ReceiptView` structure from `near-primitives`. #### `Receipt` Structure Definition ```ts export class Receipt implements Events { constructor( readonly receiptKind: ReceiptKind, readonly receiptId: string, readonly receiverId: string, readonly predecessorId: string, readonly status: ExecutionStatus, readonly executionOutcomeId?: string | undefined, readonly logs: string[] = []) { } ... // helper methods ommitted for brevity } ``` #### `Receipt` Fields ##### `receiptKind` Defined the type of the `Receipt`: `Action` or `Data` representing the `ActionReceipt` and `DataReceipt`. ##### `receiptId` The ID of the `Receipt` of the `CryptoHash` type. ##### `receiverId` The receiver account id of the `Receipt`. ##### `predecessorId` The predecessor account id of the `Receipt`. ##### `status` Represents the status of `ExecutionOutcome` of the `Receipt`. See the `ExecutionStatus` enum section for the details. ##### `executionOutcomeId` The id of the `ExecutionOutcome` for the `Receipt`. Returns `null` if the `Receipt` isn’t executed yet and has a postponed status. ##### `logs` The original logs of the corresponding `ExecutionOutcome` of the `Receipt`. Note: not all of the logs might be parsed as JSON Events (`Events`). #### `Receipt` Helper Methods ```ts export class Receipt { ... // constructor ommitted for brevity get events(): Event[] {} static fromOutcomeWithReceipt(outcomeWithReceipt: OutcomeWithReceipt): Receipt {} } ``` ##### `Receipt.events(): Events[]` Returns an Array of `Events` for the `Receipt`, if any. This might be empty if the `logs` field is empty or doesn’t contain JSON Events compatible log records. ### `Event` This structure is an ephemeral entity to provide access to the [Events Standard](https://github.com/near/NEPs/blob/master/neps/nep-0297.md) structure and keep data about the related `Receipt` for convenience. #### Interface for Capturing Data About an Event in `handleStreamerMessage()` The interface to capture data about an event has the following arguments: - `standard`: name of standard, e.g. nep171 - `version`: e.g. 1.0.0 - `event`: type of the event, e.g. nft_mint - `data`: associate event data. Strictly typed for each set {standard, version, event} inside corresponding NEP #### `Event` Structure Definition ```ts export class Event { constructor( readonly relatedReceiptId: string, readonly rawEvent: RawEvent) { } ... // helper methods ommitted for brevity } ``` #### `Event` Methods ```ts export class Event { ... // constructor ommitted for brevity static fromLog(log: string): Event {} } ``` ### `Transaction` A representation of the `IndexerTransactionWithOutcome` from `near-indexer-primitives` which is an ephemeral structure combining `SignedTransactionView` from `near-primitives` and `IndexerExecutionOutcomeWithOptionalReceipt` from `near-indexer-primitives`. This structure is very similar to `Receipt`. Unlike `Receipt`, a `Transaction` has a few additional fields like `signerId`, `signature`, and `operations`. #### `Transaction` Structure Definition ```ts export class Transaction { constructor( readonly transactionHash: string, readonly signerId: string, readonly signerPublicKey: string, readonly signature: string, readonly receiverId: string, readonly status: ExecutionStatus, readonly executionOutcomeId: string, readonly operations: Operation[]) { } } ``` ##### `Transaction.transactionHash` Returns the hash of the `Transaction` in `CryptoHash`. ##### `Transaction.signerId` Returns the signer account id of the `Transaction`. ##### `Transaction.signerPublicKey` Returns the `PublicKey` of the signer of the `Transaction`. ##### `Transaction.signature` Returns the `Signature` the `Transaction` was signed with. ##### `Transaction.receiverId` Returns the receiver account id of the `Transaction`. ##### `Transaction.status` Returns the status of the `Transaction` as `ExecutionStatus`. ##### `Transaction.executionOutcomeId` Returns the id of the `ExecutionOutcome` for the `Transaction`. ##### `Transaction.operations` Returns an Array of `Operation` for the `Transaction`. ### `StateChange` This structure is almost an identical copy of the `StateChangeWithCauseView` from `near-primitives` with a propagated additional field `affectedAccountId`. #### `StateChange` Structure Definition ```ts export class StateChange { constructor( readonly cause: StateChangeCause, readonly value: StateChangeValue ) {} get affectedAccountId(): string {} static fromStateChangeView(stateChangeView: StateChangeWithCauseView) {} } ``` ##### `StateChange.cause` Returns the `cause` of the `StateChange`. ##### `StateChange.value` Returns the `value` of the `StateChange`. ##### `StateChange.affectedAccountId(): string` Returns the account id of the `StateChange`. ##### `StateChange.fromStateChangeView(stateChangeView: StateChangeWithCauseView): StateChange` Returns the `StateChange` from the `StateChangeWithCauseView`. Created for backward compatibility.