Class: CairoClassHash

Defined in: src/utils/cairoDataTypes/classHash.ts:29

A Cairo core::starknet::class_hash::ClassHash : the hash identifying a declared class.

On the wire it is a field element like any other, so what this class adds over CairoFelt252 is the bound of the Cairo ClassHash type : [0, 2^251), the same range as the Cairo type of an address, and narrower than the field. The 252-bit bound the RPC spec states is looser, and never the one that binds.

A number, a bigint, a decimal string and a hexadecimal string are all read as the same number. Text is not an accepted input : a class hash spelled as words is a mistake, not a value.

Example

// the same hash, reached three ways
new CairoClassHash('0x1234').toBigInt(); // 4660n
new CairoClassHash(4660).toBigInt(); //    4660n
new CairoClassHash('4660').toBigInt(); //  4660n

Constructors

Constructor

new CairoClassHash(data): CairoClassHash

Defined in: src/utils/cairoDataTypes/classHash.ts:60

Build from a number or a numeric string, refusing text and anything outside the ClassHash range.

Parameters

data

unknown

the hash to carry, within [0, 2^251 - 1]

Returns

CairoClassHash

Throws

when the value is text, a decimal number, not a felt252 input, or out of the ClassHash range

Example

const result = new CairoClassHash('0x1234').toApiRequest();
// result = ["4660"]

Properties

abiSelector

static abiSelector: "core::starknet::class_hash::ClassHash" = Literal.ClassHash

Defined in: src/utils/cairoDataTypes/classHash.ts:48

The abi type this class serializes.

Example

const result = CairoClassHash.abiSelector;
// result = "core::starknet::class_hash::ClassHash"

---

data

data: bigint

Defined in: src/utils/cairoDataTypes/classHash.ts:38

The hash, always as a bigint.

Example

const result = new CairoClassHash('0x1234').data;
// result = 4660n

Methods

validate()

static validate(data): void

Defined in: src/utils/cairoDataTypes/classHash.ts:129

Throw unless the value can be carried by a ClassHash.

Text is refused first, then a number with a decimal part. A number or a bigint is read as it is, so that a negative one reaches the range check. Anything else is read as a felt252 — which is what refuses a null, an object or an unsupported type. The value is finally checked against the range of the Cairo ClassHash type, [0, 2^251), which is narrower than the field.

Parameters

data

unknown

the value to check

Returns

void

Throws

when the value is text, a decimal number, not a felt252 input, or out of the ClassHash range

Example

CairoClassHash.validate('0x1234'); // passes
CairoClassHash.validate('abc');
// throws Error("Invalid input: a ClassHash cannot be built from text")
CairoClassHash.validate(2n ** 251n);
// throws Error("Value is out of ClassHash range [0, 3618502788666131106986593281521497120414687020801267626233049500247285301247]")
CairoClassHash.validate(-1);
// throws Error("Value is out of ClassHash range [0, 3618502788666131106986593281521497120414687020801267626233049500247285301247]")

---

is()

static is(data): boolean

Defined in: src/utils/cairoDataTypes/classHash.ts:161

Can this value be carried by a ClassHash?

The non-throwing form of CairoClassHash.validate, so it answers false for every input that one refuses, whatever the reason.

Parameters

data

unknown

the value to test

Returns

boolean

true when the value fits in a ClassHash

Example

const result = CairoClassHash.is('0x1234');
// result = true
const result2 = CairoClassHash.is('abc');
// result2 = false     (text, not a number)

---

isAbiType()

static isAbiType(abiType): boolean

Defined in: src/utils/cairoDataTypes/classHash.ts:182

Is this abi type the one this class serializes?

Parameters

abiType

string

the abi type to test

Returns

boolean

true for core::starknet::class_hash::ClassHash

Example

const result = CairoClassHash.isAbiType('core::starknet::class_hash::ClassHash');
// result = true
const result2 = CairoClassHash.isAbiType('core::felt252');
// result2 = false

---

factoryFromApiResponse()

static factoryFromApiResponse(responseIterator): CairoClassHash

Defined in: src/utils/cairoDataTypes/classHash.ts:197

Read one ClassHash off a contract response, advancing the iterator past it.

Parameters

responseIterator

Iterator<string>

the response felts, positioned on this hash

Returns

CairoClassHash

the hash that was read

Example

const response = ['0x1234'];
const result = CairoClassHash.factoryFromApiResponse(response.values()).toBigInt();
// result = 4660n

---

toApiRequest()

toApiRequest(): string[]

Defined in: src/utils/cairoDataTypes/classHash.ts:74

Serialize to the single felt a contract call carries.

Returns

string[]

one decimal-string felt, flagged as compiled

Example

const result = new CairoClassHash('0x1234').toApiRequest();
// result = ["4660"]

---

toBigInt()

toBigInt(): bigint

Defined in: src/utils/cairoDataTypes/classHash.ts:87

The hash as a number.

Returns

bigint

the number this hash holds

Example

const result = new CairoClassHash('0x1234').toBigInt();
// result = 4660n

---

toHexString()

toHexString(): string

Defined in: src/utils/cairoDataTypes/classHash.ts:105

The hash in hexadecimal, without padding.

The 64 hex digits a class hash is usually written with are not restored here : leading zeros are dropped, as they are everywhere else in the library.

Returns

string

the hash as a 0x-prefixed hex string

Example

const result = new CairoClassHash(4660).toHexString();
// result = "0x1234"
const result2 = new CairoClassHash('0x0034').toHexString();
// result2 = "0x34"     (four digits in, two out)