SmartContract

bitcoinjs-lib v0.2.9-beta.16

---

bitcoinjs-lib / SmartContract

Class: SmartContract\<StateT>

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:128

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

Onchain

Example

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

Extends

• AbstractContract

Type Parameters

• StateT extends StructObject = undefined

Implements

• Taprootable

Constructors

new SmartContract()

new SmartContract\<StateT>(...args): SmartContract\<StateT>

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:178

Parameters

args

...SupportedParamType[]

Returns

SmartContract\<StateT>

Overrides

AbstractContract.constructor

Backtrace

backtraceToOutpoint()

backtraceToOutpoint(backtraceInfo, genesisOutpoint): boolean

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:815

Check whether the contract can be traced back to the genesis outpoint.

Parameters

backtraceInfo

BacktraceInfo

the backtrace info to verify, including prevTx and prevPrevTx informations

genesisOutpoint

ByteString

expected genesis outpoint to be traced back to

Returns

boolean

true if the contract can be backtraced to the genesis outpoint. Otherwise false.

Onchain

Overrides

AbstractContract.backtraceToOutpoint

---

backtraceToScript()

backtraceToScript(backtraceInfo, genesisScript): boolean

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:827

Check whether the contract can be traced back to the genesis script.

Parameters

backtraceInfo

BacktraceInfo

the backtrace info to verify, including prevTx and prevPrevTx informations

genesisScript

ByteString

expected genesis script to be traced back to

Returns

boolean

true if the contract can be backtraced to the genesis script. Otherwise false.

Onchain

Overrides

AbstractContract.backtraceToScript

Other

controlBlock

controlBlock: string

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:664

In Taproot, a control block is a data structure used during script path spends to prove that a particular script is part of the Taproot output's script tree.

Implementation of

Taprootable.controlBlock

---

lockingScript

readonly lockingScript: Script

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:162

Locking script corresponding to the SmartContract

---

state

state: StateT

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:157

The state of the contract UTXO, usually committed to the first OP_RETURN output, is revealed when spending.

Onchain

---

tweakedPubkey

tweakedPubkey: string

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:669

In Taproot, tweaking a public key involves modifying an existing public key to create a new one that embeds additional information, such as commitments to scripts or data.

Implementation of

Taprootable.tweakedPubkey

---

artifact

static artifact: Artifact

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:135

Bitcoin Contract Artifact

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changeInfo

Get Signature

get changeInfo(): TxOut

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:587

Get the change info of the change output for current psbt.

Onchain

Returns

TxOut

the change info of current psbt

---

ctx

Get Signature

get ctx(): IContext

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:384

Get the context details of the current PSBT input in which this contract is called or spent.

Onchain

Returns

IContext

Overrides

AbstractContract.ctx

---

debug

Get Signature

get debug(): object

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:596

A set of functions for debugging contracts, which can only be called in @method methods.

Onchain

Returns

object

diffOutputs()

diffOutputs: (outputsByte) => void

Parameters

outputsByte

ByteString

Returns

void

---

inputContext

Get Signature

get inputContext(): InputContext

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:437

Get the context of the current PSBT input in which this contract is called or spent.

Returns

InputContext

the context of the current PSBT input

---

spentPsbt

Get Signature

get spentPsbt(): Contextual

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:424

Returns

Contextual

---

tapScript

Get Signature

get tapScript(): string

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:447

tapScript

Returns

string

Implementation of

Taprootable.tapScript

---

appendStateOutput()

appendStateOutput(output, stateHash): Int32

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:296

A built-in function to append an output with a new stateHash.

Parameters

output

ByteString

the output bytes

stateHash

Ripemd160

the hash160 of the contract state

Returns

Int32

state outputs count

Onchain

Overrides

AbstractContract.appendStateOutput

---

buildChangeOutput()

buildChangeOutput(): ByteString

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:271

A built-in function to create an [change output][https://en.bitcoin.it/wiki/Change](https://en.bitcoin.it/wiki/Change).

Returns

ByteString

Onchain

Overrides

AbstractContract.buildChangeOutput

---

buildStateOutputs()

buildStateOutputs(): ByteString

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:317

A built-in function to create all outputs added by appendStateOutput()

Returns

ByteString

an output containing the new state

Onchain

Overrides

AbstractContract.buildStateOutputs

---

checkInputStateHash()

checkInputStateHash(inputIndex, stateHash): boolean

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:361

check StateHash of the input. By default, the system checks the StateHash of all inputs. If you use this function to specify checking only specific inputs' StateHash, you must set the autoCheckInputStateHash option in the @method() decorator to false.

Parameters

inputIndex

Int32

index of the input

stateHash

ByteString

stateHash of the input

Returns

boolean

success if stateHash is valid

Onchain

Overrides

AbstractContract.checkInputStateHash

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checkOutputs()

checkOutputs(outputs): boolean

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:631

Check the outputs with the context of current transaction.

Parameters

outputs

ByteString

the expected serialized outputs of the current transaction

Returns

boolean

true if the outputs are not consistent with the transaction context, otherwise false.

Onchain

Overrides

AbstractContract.checkOutputs

---

checkSHPreimage()

checkSHPreimage(shPreimage): boolean

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:242

Using the [OP_PUSH_TX][https://medium.com/@xiaohuiliu/op-push-tx-3d3d279174c1](https://medium.com/@xiaohuiliu/op-push-tx-3d3d279174c1) technique, check if shPreimage is the preimage of the current transaction.

Parameters

shPreimage

SHPreimage

Returns

boolean

true if shPreimage is the preimage of the current transaction. Otherwise false.

Onchain

Overrides

AbstractContract.checkSHPreimage

---

cltv()

cltv(nLockTime): boolean

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:695

Checks a locktime parameter with the transaction's locktime. There are two times of nLockTime: lock-by-blockheight and lock-by-blocktime, distinguished by whether nLockTime < LOCKTIME_THRESHOLD = 500000000

See the corresponding code on bitcoin core: https://github.com/bitcoin/bitcoin/blob/ffd75adce01a78b3461b3ff05bcc2b530a9ce994/src/script/interpreter.cpp#L1129

See the bip65 for specification https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki#summary

Parameters

nLockTime

Int32

the locktime read from the script

Returns

boolean

true if the transaction's locktime is less than or equal to the transaction's locktime

Onchain

Overrides

AbstractContract.cltv

---

csv()

csv(nSequence): boolean

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:744

Checks a sequence parameter with the transaction's sequence.

Parameters

nSequence

Int32

the sequence read from the script

Returns

boolean

true if the transaction's sequence is less than or equal to the transaction's sequence

Onchain

Overrides

AbstractContract.csv

---

methodCallToWitness()

methodCallToWitness(): Witness

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:644

get all witness

Returns

Witness

all witness that call the contract

---

setSighashType()

setSighashType(sigHashType): void

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:428

Parameters

sigHashType

SigHashType

Returns

void

---

spentFromInput()

spentFromInput(psbt, inputIndex): void

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:419

Mark the contract instance as spent from the input of the PSBT.

Parameters

psbt

Contextual

inputIndex

number

Returns

void

---

create()

static create\<T>(this, ...args): InstanceType\<T>

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:225

Used to create an instance of a smart contract. If your smart contract has a base class, you must use this method to instantiate it.

Type Parameters

• T extends (...args) => InstanceType\<T>

Parameters

this

T

args

...ConstructorParameters\<T>

Returns

InstanceType\<T>

---

loadArtifact()

static loadArtifact(artifact): typeof SmartContract

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:169

This function is usually called on the frontend. The contract class needs to call this function before instantiating.

Parameters

artifact

Artifact

a contract artifact json object

Returns

typeof SmartContract

---

stateHash()

static stateHash\<T>(this, state): Ripemd160

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:333

Calculate the hash of all states of the current contract

Type Parameters

• T extends StructObject

Parameters

this

(...args) => SmartContract\<T>

state

T

state of the contract

Returns

Ripemd160

hash160 of the state

Onchain

Overrides

AbstractContract.stateHash

Signature Verification

checkSig()

checkSig(signature, publickey, errorMsg): boolean

Defined in: packages/scrypt-ts-btc/src/smart-contract/smartContract.ts:252

A built-in function verifies an Schnorr signature. It takes two inputs from the stack, a public key (on top of the stack) and an Schnorr signature in its DER_CANONISED format concatenated with sighash flags. It outputs true or false on the stack based on whether the signature check passes or fails. [see][https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki#specification](https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki#specification)

Parameters

signature

Sig

publickey

PubKey

errorMsg

string = 'signature check failed'

Returns

boolean

Onchain

Overrides

AbstractContract.checkSig