SmartContract
SnarkyJS / Modules / SmartContract
Class: SmartContract
The main zkapp class. To write a zkapp, extend this class as such:
class YourSmartContract extends SmartContract {
// your smart contract code here
}
Table of contents
Constructors
Properties
- #_senderState
- #executionState
- address
- events
- tokenId
- _maxProofsVerified
- _methodMetadata
- _methods
- _provers
- _verificationKey
Accessors
Methods
- approve
- deploy
- emitEvent
- fetchEvents
- init
- newSelf
- requireSignature
- send
- setPermissions
- setValue
- sign
- skipAuthorization
- Proof
- analyzeMethods
- compile
- digest
- runOutsideCircuit
Constructors
constructor
• new SmartContract(address, tokenId?)
Parameters
| Name | Type |
|---|---|
address | PublicKey |
tokenId? | Field |
Defined in
Properties
#_senderState
• Private #_senderState: Object
Type declaration
| Name | Type |
|---|---|
sender | PublicKey |
transactionId | number |
Defined in
#executionState
• Private #executionState: undefined | ExecutionState
Defined in
address
• address: PublicKey
Defined in
events
• events: Object = {}
A list of event types that can be emitted using this.emitEvent()`.
Index signature
▪ [key: string]: FlexibleProvablePure<any>
Defined in
tokenId
• tokenId: Field
Defined in
_maxProofsVerified
▪ Static Optional _maxProofsVerified: 0 | 2 | 1
Defined in
_methodMetadata
▪ Static Optional _methodMetadata: Record<string, { actions: number ; digest: string ; gates: Gate[] ; hasReturn: boolean ; rows: number }>
Defined in
_methods
▪ Static Optional _methods: MethodInterface[]
Defined in
_provers
▪ Static Optional _provers: Prover[]
Defined in
_verificationKey
▪ Static Optional _verificationKey: Object
Type declaration
| Name | Type |
|---|---|
data | string |
hash | Field |
Defined in
Accessors
account
• get account(): Account
Current account of the SmartContract.
Returns
Account
Defined in
balance
• get balance(): Object
Balance of this SmartContract.
Returns
Object
| Name | Type |
|---|---|
addInPlace | (x: string | number | bigint | UInt64 | UInt32 | Int64) => void |
subInPlace | (x: string | number | bigint | UInt64 | UInt32 | Int64) => void |
Defined in
currentSlot
• get currentSlot(): CurrentSlot
Current global slot on the network. This is the slot at which this transaction is included in a block. Since we cannot know this value
at the time of transaction construction, this only has the assertBetween() method but no get() (impossible to implement)
or assertEquals() (confusing, because the developer can't know the exact slot at which this will be included either)
Returns
CurrentSlot
Defined in
network
• get network(): Network
Current network state of the SmartContract.
Returns
Network
Defined in
self
• get self(): AccountUpdate
Returns the current AccountUpdate associated to this SmartContract.
Returns
Defined in
sender
• get sender(): PublicKey
The public key of the current transaction's sender account.
Throws an error if not inside a transaction, or the sender wasn't passed in.
Warning: The fact that this public key equals the current sender is not part of the proof. A malicious prover could use any other public key without affecting the validity of the proof.
Returns
Defined in
token
• get token(): Object
Token of the SmartContract.
Returns
Object
| Name | Type |
|---|---|
id | Field |
parentTokenId | Field |
tokenOwner | PublicKey |
burn | (__namedParameters: { address: PublicKey | AccountUpdate | SmartContract ; amount: number | bigint | UInt64 }) => AccountUpdate |
mint | (__namedParameters: { address: PublicKey | AccountUpdate | SmartContract ; amount: number | bigint | UInt64 }) => AccountUpdate |
send | (__namedParameters: { amount: number | bigint | UInt64 ; from: PublicKey | AccountUpdate | SmartContract ; to: PublicKey | AccountUpdate | SmartContract }) => AccountUpdate |
Defined in
tokenSymbol
• get tokenSymbol(): Object
Deprecated
use this.account.tokenSymbol
Returns
Object
| Name | Type |
|---|---|
set | (tokenSymbol: string) => void |
Defined in
Methods
approve
▸ approve(updateOrCallback, layout?): AccountUpdate
Approve an account update or callback. This will include the account update in the zkApp's public input, which means it allows you to read and use its content in a proof, make assertions about it, and modify it.
If this is called with a callback as the first parameter, it will first extract the account update produced by that callback. The extracted account update is returned.
\@method myApprovingMethod(callback: Callback) {
let approvedUpdate = this.approve(callback);
}
Under the hood, "approving" just means that the account update is made a child of the zkApp in the
tree of account updates that forms the transaction.
The second parameter layout allows you to also make assertions about the approved update's own children,
by specifying a certain expected layout of children. See Layout.
Parameters
| Name | Type |
|---|---|
updateOrCallback | AccountUpdate | Callback<any> |
layout? | AccountUpdatesLayout |
Returns
The account update that was approved (needed when passing in a Callback)
Defined in
deploy
▸ deploy(«destructured»?): void
Deploys a SmartContract.
let tx = await Mina.transaction(sender, () => {
AccountUpdate.fundNewAccount(sender);
zkapp.deploy();
});
tx.sign([senderKey, zkAppKey]);
Parameters
| Name | Type |
|---|---|
«destructured» | Object |
› verificationKey? | Object |
› verificationKey.data | string |
› verificationKey.hash | string | Field |
› zkappKey? | PrivateKey |
Returns
void
Defined in
emitEvent
▸ emitEvent<K>(type, event): void
Emits an event. Events will be emitted as a part of the transaction and can be collected by archive nodes.
Type parameters
| Name | Type |
|---|---|
K | extends string | number |
Parameters
| Name | Type |
|---|---|
type | K |
event | any |
Returns
void
Defined in
fetchEvents
▸ fetchEvents(start?, end?): Promise<{ blockHash: string ; blockHeight: UInt32 ; chainStatus: string ; event: { data: ProvablePure<any> ; transactionInfo: { transactionHash: string ; transactionMemo: string ; transactionStatus: string } } ; globalSlot: UInt32 ; parentBlockHash: string ; type: string }[]>
Asynchronously fetches events emitted by this SmartContract and returns an array of events with their corresponding types.
Async
Throws
If there is an error fetching events from the Mina network.
Example
const startHeight = UInt32.from(1000);
const endHeight = UInt32.from(2000);
const events = await myZkapp.fetchEvents(startHeight, endHeight);
console.log(events);
Parameters
| Name | Type | Description |
|---|---|---|
start? | UInt32 | The start height of the events to fetch. |
end? | UInt32 | The end height of the events to fetch. If not provided, fetches events up to the latest height. |
Returns
Promise<{ blockHash: string ; blockHeight: UInt32 ; chainStatus: string ; event: { data: ProvablePure<any> ; transactionInfo: { transactionHash: string ; transactionMemo: string ; transactionStatus: string } } ; globalSlot: UInt32 ; parentBlockHash: string ; type: string }[]>
A promise that resolves to an array of objects, each containing the event type and event data for the specified range.
Defined in
init
▸ init(): void
SmartContract.init() will be called only when a SmartContract will be first deployed, not for redeployment.
This method can be overridden as follows
class MyContract extends SmartContract {
init() {
super.init();
this.account.permissions.set(...);
this.x.set(Field(1));
}
}
Returns
void
Defined in
newSelf
▸ newSelf(): AccountUpdate
Same as SmartContract.self but explicitly creates a new AccountUpdate.
Returns
Defined in
requireSignature
▸ requireSignature(): void
Use this command if the account update created by this SmartContract should be signed by the account owner, instead of authorized with a proof.
Note that the smart contract's Permissions determine which updates have to be (can be) authorized by a signature.
If you only want to avoid creating proofs for quicker testing, we advise you to
use LocalBlockchain({ proofsEnabled: false }) instead of requireSignature(). Setting
proofsEnabled to false allows you to test your transactions with the same authorization flow as in production,
with the only difference being that quick mock proofs are filled in instead of real proofs.
Returns
void
Defined in
send
▸ send(args): AccountUpdate
Parameters
| Name | Type |
|---|---|
args | Object |
args.amount | number | bigint | UInt64 |
args.to | PublicKey | AccountUpdate | SmartContract |
Returns
Defined in
setPermissions
▸ setPermissions(permissions): void
Deprecated
use this.account.permissions.set()
Parameters
| Name | Type |
|---|---|
permissions | Permissions |
Returns
void
Defined in
setValue
▸ setValue<T>(maybeValue, value): void
Deprecated
use this.account.<field>.set()
Type parameters
| Name |
|---|
T |
Parameters
| Name | Type |
|---|---|
maybeValue | SetOrKeep<T> |
value | T |
Returns
void
Defined in
sign
▸ sign(zkappKey?): void
Deprecated
this.sign() is deprecated in favor of this.requireSignature()
Parameters
| Name | Type |
|---|---|
zkappKey? | PrivateKey |
Returns
void
Defined in
skipAuthorization
▸ skipAuthorization(): void
Use this command if the account update created by this SmartContract should have no authorization on it, instead of being authorized with a proof.
WARNING: This is a method that should rarely be useful. If you want to disable proofs for quicker testing, take a look
at LocalBlockchain({ proofsEnabled: false }), which causes mock proofs to be created and doesn't require changing the
authorization flow.
Returns
void
Defined in
Proof
▸ Static Proof(): typeof __class
Returns a Proof type that belongs to this SmartContract.
Returns
typeof __class
Defined in
analyzeMethods
▸ Static analyzeMethods(): Record<string, { actions: number ; digest: string ; gates: Gate[] ; hasReturn: boolean ; rows: number }>
This function is run internally before compiling a smart contract, to collect metadata about what each of your smart contract methods does.
For external usage, this function can be handy because calling it involves running all methods in the same "mode" as compile() does,
so it serves as a quick-to-run check for whether your contract can be compiled without errors, which can greatly speed up iterating.
analyzeMethods() will also return the number of rows of each of your method circuits (i.e., the number of constraints in the underlying proof system),
which is a good indicator for circuit size and the time it will take to create proofs.
To inspect the created circuit in detail, you can look at the returned gates.
Note: If this function was already called before, it will short-circuit and just return the metadata collected the first time.
Returns
Record<string, { actions: number ; digest: string ; gates: Gate[] ; hasReturn: boolean ; rows: number }>
an object, keyed by method name, each entry containing:
rowsthe size of the constraint system created by this methoddigesta digest of the method circuithasReturna boolean indicating whether the method returns a valueactionsthe number of actions the method dispatchesgatesthe constraint system, represented as an array of gates
Defined in
compile
▸ Static compile(): Promise<{ provers: Prover[] ; verificationKey: { data: string = verificationKey_.data; hash: Field } ; verify: (statement: Statement<Uint8Array>, proof: unknown) => Promise<boolean> }>
Compile your smart contract.
This generates both the prover functions, needed to create proofs for running @methods,
and the verification key, needed to deploy your zkApp.
Although provers and verification key are returned by this method, they are also cached internally and used when needed, so you don't actually have to use the return value of this function.
Under the hood, "compiling" means calling into the lower-level Pickles and Kimchi libraries to create multiple prover & verifier indices (one for each smart contract method as part of a "step circuit" and one for the "wrap circuit" which recursively wraps it so that proofs end up in the original finite field). These are fairly expensive operations, so expect compiling to take at least 20 seconds, up to several minutes if your circuit is large or your hardware is not optimal for these operations.
Returns
Promise<{ provers: Prover[] ; verificationKey: { data: string = verificationKey_.data; hash: Field } ; verify: (statement: Statement<Uint8Array>, proof: unknown) => Promise<boolean> }>
Defined in
digest
▸ Static digest(): string
Computes a hash of your smart contract, which will reliably change whenever one of your method circuits changes. This digest is quick to compute. it is designed to help with deciding whether a contract should be re-compiled or a cached verification key can be used.
Returns
string
the digest, as a hex string
Defined in
runOutsideCircuit
▸ Static runOutsideCircuit(run): void
Parameters
| Name | Type |
|---|---|
run | () => void |
Returns
void