SmartContract
The main zkapp class. To write a zkapp, extend this class as such:
class YourSmartContract extends SmartContract {
// your smart contract code here
}
Extends
SmartContractBase
Constructors
new SmartContract(address, tokenId)
new SmartContract(address: PublicKey, tokenId?: Field): SmartContract
Parameters
• address: PublicKey
• tokenId?: Field
Returns
Overrides
SmartContractBase.constructor
Source
Properties
address
address: PublicKey;
Source
events
events: {} = {};
A list of event types that can be emitted using this.emitEvent()`.
Index signature
[key: string]: FlexibleProvablePure\<any>
Source
sender
sender: {
self: SmartContract;
getAndRequireSignature: PublicKey;
getUnconstrained: PublicKey;
};
self
self: SmartContract;
getAndRequireSignature()
Returns
getUnconstrained()
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
Source
tokenId
tokenId: Field;
Source
_maxProofsVerified?
static optional _maxProofsVerified: 0 | 2 | 1;
Source
_methodMetadata?
static optional _methodMetadata: Record<string, {
actions: number;
digest: string;
gates: Gate[];
rows: number;
}>;
Source
_methods?
static optional _methods: MethodInterface[];
Source
_provers?
static optional _provers: Prover[];
Source
_verificationKey?
static optional _verificationKey: {
data: string;
hash: Field;
};
data
data: string;
hash
hash: Field;
Source
Accessors
account
get account(): Account
Current account of the SmartContract.
Returns
Account
Source
balance
get balance(): {
addInPlace: void;
subInPlace: void;
}
Balance of this SmartContract.
Returns
{
addInPlace: void;
subInPlace: void;
}
addInPlace()
Parameters
• x:
| string
| number
| bigint
| UInt64
| UInt32
| Int64
Returns
void
subInPlace()
Parameters
• x:
| string
| number
| bigint
| UInt64
| UInt32
| Int64
Returns
void
Source
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
Source
network
get network(): Network
Current network state of the SmartContract.
Returns
Network
Source
self
get self(): AccountUpdate
Returns the current AccountUpdate associated to this SmartContract.
Returns
Source
Methods
approve()
approve(update: AccountUpdate | AccountUpdateTree | AccountUpdateForest): void
Approve an account update or tree / forest of updates. Doing this means you include the account update in the zkApp's public input, which allows you to read and use its content in a proof, make assertions about it, and modify it.
`@method` myApprovingMethod(update: AccountUpdate) {
this.approve(update);
// read balance on the account (for example)
let balance = update.account.balance.getAndRequireEquals();
}
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. Similarly, if you pass in an AccountUpdateTree, the entire tree will become a subtree of the zkApp's account update.
Passing in a forest is a bit different, because it means you set the entire children of the zkApp's account update
at once. approve() will fail if the zkApp's account update already has children, to prevent you from accidentally
excluding important information from the public input.
Parameters
• update: AccountUpdate | AccountUpdateTree | AccountUpdateForest
Returns
void
Source
deploy()
deploy(__namedParameters: {
verificationKey: {
data: string;
hash: string | Field;
};
}): Promise<void>
Deploys a SmartContract.
let tx = await Mina.transaction(sender, async () => {
AccountUpdate.fundNewAccount(sender);
await zkapp.deploy();
});
tx.sign([senderKey, zkAppKey]);
Parameters
• __namedParameters= {}
• __namedParameters.verificationKey?
• __namedParameters.verificationKey.data: string
• __namedParameters.verificationKey.hash: string | Field
Returns
Promise\<void>
Source
emitEvent()
emitEvent<K>(type: K, event: any): void
Emits an event. Events will be emitted as a part of the transaction and can be collected by archive nodes.
Type parameters
• K extends string | number
Parameters
• type: K
• event: any
Returns
void
Source
fetchEvents()
fetchEvents(start?: UInt32, end?: UInt32): 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.
Parameters
• start?: UInt32= undefined
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.
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);
Source
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
Source
newSelf()
newSelf(methodName?: string): AccountUpdate
Same as SmartContract.self but explicitly creates a new AccountUpdate.
Parameters
• methodName?: string
Returns
Source
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
Source
send()
send(args: {
amount: number | bigint | UInt64;
to: PublicKey | AccountUpdate | SmartContract;
}): AccountUpdate
Parameters
• args
• args.amount: number | bigint | UInt64
• args.to: PublicKey | AccountUpdate | SmartContract
Returns
Source
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
Source
Proof()
static Proof(): typeof __class
Returns a Proof type that belongs to this SmartContract.
Returns
typeof __class
Source
analyzeMethods()
static analyzeMethods(__namedParameters: {
printSummary: false;
}): Promise<Record<string, {
actions: number;
digest: string;
gates: Gate[];
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.
Parameters
• __namedParameters= {}
• __namedParameters.printSummary: undefined | boolean= false
Returns
Promise\<Record\<string, {
actions: number;
digest: string;
gates: Gate[];
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 circuitactionsthe number of actions the method dispatchesgatesthe constraint system, represented as an array of gates
Source
compile()
static compile(__namedParameters: {
cache: Cache.FileSystemDefault;
forceRecompile: false;
}): Promise<{
provers: Prover[];
verificationKey: {
data: string;
hash: Field;
};
verify: (statement: Statement<FieldConst>, 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.
Parameters
• __namedParameters= {}
• __namedParameters.cache: undefined | Cache= Cache.FileSystemDefault
• __namedParameters.forceRecompile: undefined | boolean= false
Returns
Promise\<{
provers: Prover[];
verificationKey: {
data: string;
hash: Field;
};
verify: (statement: Statement\<FieldConst>, proof: unknown) => Promise\<boolean>;
}>
provers
provers: Prover[];verificationKey
verificationKey: {
data: string;
hash: Field;
};verificationKey.data
data: string;verificationKey.hash
hash: Field;verify()
verify: (statement: Statement<FieldConst>, proof: unknown) => Promise<boolean>;Parameters
• statement:
Statement\<FieldConst>• proof:
unknownReturns
Promise\<boolean>
Source
digest()
static digest(): Promise<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
Promise\<string>
the digest, as a hex string
Source
runOutsideCircuit()
static runOutsideCircuit(run: () => void): void
Parameters
• run
Returns
void