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Version: 2.15.0

SmartContract

Defined in: lib/mina/v1/zkapp.ts:516

The main zkapp class. To write a zkapp, extend this class as such:

class YourSmartContract extends SmartContract {
  // your smart contract code here
}

Extends​

  • SmartContractBase

Extended by​

Constructors​

Constructor​

new SmartContract(address: PublicKey, tokenId?: Field): SmartContract;

Defined in: lib/mina/v1/zkapp.ts:552

Parameters​

address​

PublicKey

tokenId?​

Field

Returns​

SmartContract

Overrides​

SmartContractBase.constructor

Properties​

address​

address: PublicKey;

Defined in: lib/mina/v1/zkapp.ts:517

events​

events: {
[key: string]: FlexibleProvablePure<any>;
} = {};

Defined in: lib/mina/v1/zkapp.ts:970

A list of event types that can be emitted using this.emitEvent()`.

Index Signature​

[key: string]: FlexibleProvablePure<any>

sender​

sender: {
  self: SmartContract;
  getAndRequireSignature: PublicKey;
  getUnconstrained: PublicKey;
};

Defined in: lib/mina/v1/zkapp.ts:862

self​

self: SmartContract;

getAndRequireSignature()​

getAndRequireSignature(): PublicKey;

Return a public key that is forced to sign this transaction.

Note: This doesn't prove that the return value is the transaction sender, but it proves that whoever created the transaction controls the private key associated with the returned public key.

Returns​

PublicKey

getUnconstrained()​

getUnconstrained(): 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.

Consider using this.sender.getAndRequireSignature() if you need to prove that the sender controls this account.

Returns​

PublicKey

tokenId​

tokenId: Field;

Defined in: lib/mina/v1/zkapp.ts:518

_methodMetadata?​

static optional _methodMetadata?: Record<string, {
  actions: number;
  digest: string;
  gates: Gate[];
  proofs: ProofClass[];
  rows: number;
}>;

Defined in: lib/mina/v1/zkapp.ts:527

_methods?​

static optional _methods?: MethodInterface[];

Defined in: lib/mina/v1/zkapp.ts:526

_provers?​

static optional _provers?: Prover[];

Defined in: lib/mina/v1/zkapp.ts:537

_verificationKey?​

static optional _verificationKey?: {
  data: string;
  hash: Field;
};

Defined in: lib/mina/v1/zkapp.ts:538

data​

data: string;

hash​

hash: Field;

Accessors​

account​

Get Signature​

get account(): Account;

Defined in: lib/mina/v1/zkapp.ts:914

Current account of the SmartContract.

Returns​

Account

balance​

Get Signature​

get balance(): {
  addInPlace: void;
  subInPlace: void;
};

Defined in: lib/mina/v1/zkapp.ts:964

Balance of this SmartContract.

Returns​
{
  addInPlace: void;
  subInPlace: void;
}
addInPlace()​
addInPlace(x: 
  | string
  | number
  | bigint
  | UInt64
  | UInt32
  | Int64): void;
Parameters​
x​

| string | number | bigint | UInt64 | UInt32 | Int64

Returns​

void

subInPlace()​
subInPlace(x: 
  | string
  | number
  | bigint
  | UInt64
  | UInt32
  | Int64): void;
Parameters​
x​

| string | number | bigint | UInt64 | UInt32 | Int64

Returns​

void

currentSlot​

Get Signature​

get currentSlot(): CurrentSlot;

Defined in: lib/mina/v1/zkapp.ts:928

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

network​

Get Signature​

get network(): Network;

Defined in: lib/mina/v1/zkapp.ts:920

Current network state of the SmartContract.

Returns​

Network

self​

Get Signature​

get self(): AccountUpdate;

Defined in: lib/mina/v1/zkapp.ts:820

Returns the current AccountUpdate associated to this SmartContract.

Returns​

AccountUpdate

Methods​

approve()​

approve(update: 
  | AccountUpdate
  | AccountUpdateTree
  | AccountUpdateForest): void;

Defined in: lib/mina/v1/zkapp.ts:953

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

deploy()​

deploy(__namedParameters?: {
  verificationKey?: {
     data: string;
     hash: string | Field;
  };
}): Promise<void>;

Defined in: lib/mina/v1/zkapp.ts:658

Deploys a SmartContract.

let tx = await Mina.transaction(sender, async () => {
  AccountUpdate.fundNewAccount(sender);
  await zkapp.deploy();
});
tx.sign([senderKey, zkAppKey]);

Parameters​

__namedParameters?​
verificationKey?​

{ data: string; hash: string | Field; }

verificationKey.data​

string

verificationKey.hash​

string | Field

Returns​

Promise<void>

emitEvent()​

emitEvent<K>(type: K, event: any): void;

Defined in: lib/mina/v1/zkapp.ts:1017

Emits an event. Events will be emitted as a part of the transaction and can be collected by archive nodes.

Type Parameters​

K​

K extends string | number

Parameters​

type​

K

event​

any

Returns​

void

emitEventIf()​

emitEventIf<K>(
   condition: Bool, 
   type: K, 
   event: any): void;

Defined in: lib/mina/v1/zkapp.ts:978

Conditionally emits an event.

Events will be emitted as a part of the transaction and can be collected by archive nodes.

Type Parameters​

K​

K extends string | number

Parameters​

condition​

Bool

type​

K

event​

any

Returns​

void

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;
}[]>;

Defined in: lib/mina/v1/zkapp.ts:1033

Asynchronously fetches events emitted by this SmartContract and returns an array of events with their corresponding types.

Parameters​

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.

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);

init()​

init(): void;

Defined in: lib/mina/v1/zkapp.ts:768

SmartContract.init() is called when a SmartContract is first deployed. By default, it initializes the smart contract's state to zero, and sets the provedState to false.

Returns​

void

Note​

The first time any method is called on the smart contract, provedState will be set to true. The init method itself may be decorated with @method in this way. Review the examples below to see how init can be called with or without a method decorator.

Note​

init may be overridden to set state fields to values other than zero, but the method takes no arguments. Therefore, only static values may be set.

Note​

To initialize a smart contract with custom values provided as arguments, a separate method is required.

Examples​

class MyContract extends SmartContract {
 @state(Field) x = State<Field>();

 // Overwrite init to set static, non-zero values
 init() {
  super.init();
  this.x.set(Field(1));
 }

 // Use custom method to initialize dynamic values
 @method async initialize(x: Field) {
   // This method may only be called once, immediately after deployment
   this.account.provedState.getAndRequireEquals().assertFalse();

   this.x.set(x);
 }
}
class MyContract extends SmartContract {
 @state(Field) x = State<Field>();

 // Use init as a @method to set state fields to zero, and also
 // set provedState to true, making any other initialization impossible.
 @method async init() {
   super.init();
   this.x.set(Field(1));
 }

 // This method is invalid because `init` is a `@method`
 @method async initialize(x: Field) {
   // This assertion will fail because `provedState` is true after `init` is called
   this.account.provedState.getAndRequireEquals().assertFalse();

   this.x.set(x);
 }
}

newSelf()​

newSelf(methodName?: string): AccountUpdate;

Defined in: lib/mina/v1/zkapp.ts:852

Same as SmartContract.self but explicitly creates a new AccountUpdate.

Parameters​

methodName?​

string

Returns​

AccountUpdate

requireSignature()​

requireSignature(): void;

Defined in: lib/mina/v1/zkapp.ts:801

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

send()​

send(args: {
  amount: number | bigint | UInt64;
  to:   | PublicKey
     | AccountUpdate
     | SmartContract;
}): AccountUpdate;

Defined in: lib/mina/v1/zkapp.ts:957

Parameters​

args​
amount​

number | bigint | UInt64

to​

| PublicKey | AccountUpdate | SmartContract

Returns​

AccountUpdate

skipAuthorization()​

skipAuthorization(): void;

Defined in: lib/mina/v1/zkapp.ts:813

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

analyzeMethods()​

static analyzeMethods(__namedParameters?: {
  printSummary?: boolean;
}): Promise<Record<string, {
  actions: number;
  digest: string;
  gates: Gate[];
  proofs: ProofClass[];
  rows: number;
}>>;

Defined in: lib/mina/v1/zkapp.ts:1153

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?​
printSummary?​

boolean = false

Returns​

Promise<Record<string, { actions: number; digest: string; gates: Gate[]; proofs: ProofClass[]; rows: number; }>>

an object, keyed by method name, each entry containing:

  • rows the size of the constraint system created by this method
  • digest a digest of the method circuit
  • actions the number of actions the method dispatches
  • gates the constraint system, represented as an array of gates

compile()​

static compile(__namedParameters?: {
  cache?: Cache;
  forceRecompile?: boolean;
}): Promise<{
  provers: Prover[];
  verificationKey: {
     data: string;
     hash: Field;
  };
  verify: (statement: Statement<FieldConst>, proof: unknown) => Promise<boolean>;
}>;

Defined in: lib/mina/v1/zkapp.ts:580

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?​
cache?​

Cache = Cache.FileSystemDefault

forceRecompile?​

boolean = false

Returns​

Promise<{ provers: Prover[]; verificationKey: { data: string; hash: Field; }; verify: (statement: Statement<FieldConst>, proof: unknown) => Promise<boolean>; }>

digest()​

static digest(): Promise<string>;

Defined in: lib/mina/v1/zkapp.ts:621

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

getMaxProofsVerified()​

static getMaxProofsVerified(): Promise<0 | 1 | 2>;

Defined in: lib/mina/v1/zkapp.ts:632

The maximum number of proofs that are verified by any of the zkApp methods. This is an internal parameter needed by the proof system.

Returns​

Promise<0 | 1 | 2>

Proof()​

static Proof(): typeof __class;

Defined in: lib/mina/v1/zkapp.ts:543

Returns a Proof type that belongs to this SmartContract.

Returns​

typeof __class

runOutsideCircuit()​

static runOutsideCircuit(run: () => void): void;

Defined in: lib/mina/v1/zkapp.ts:1129

Parameters​

run​

() => void

Returns​

void

setVerificationKeyUnsafe()​

static setVerificationKeyUnsafe(verificationKey: {
  data: string;
  hash: string | Field;
}): void;

Defined in: lib/mina/v1/zkapp.ts:640

Manually set the verification key.

Parameters​

verificationKey​
data​

string

hash​

string | Field

Returns​

void