UInt8

o1js / Modules / UInt8

Class: UInt8

A 8 bit unsigned integer with values ranging from 0 to 255.

Hierarchy

• { value: Field = Field }

  ↳ UInt8

Table of contents

Constructors

• constructor

Properties

• value
• NUM_BITS
• Unsafe
• _isStruct
• empty
• fromFields
• fromJSON
• toAuxiliary
• toFields
• toJSON

Methods

• add
• assertEquals
• assertGreaterThan
• assertGreaterThanOrEqual
• assertLessThan
• assertLessThanOrEqual
• div
• divMod
• greaterThan
• greaterThanOrEqual
• lessThan
• lessThanOrEqual
• mod
• mul
• sub
• toBigInt
• toNumber
• toString
• toUInt32
• toUInt64
• MAXINT
• check
• checkConstant
• from
• sizeInFields
• toInput

Constructors

constructor

• new UInt8(x)

Create a UInt8 from a bigint or number. The max value of a UInt8 is 2^8 - 1 = 255.

Warning: Cannot overflow past 255, an error is thrown if the result is greater than 255.

Parameters

Name	Type
x	number | bigint | FieldVar | UInt8

Overrides

Struct({ value: Field, }).constructor

Defined in

lib/int.ts:1314

Properties

value

• value: Field = Field

Inherited from

Struct({ value: Field, }).value

Defined in

lib/int.ts:1304

---

NUM_BITS

▪ Static NUM_BITS: number = 8

Defined in

lib/int.ts:1306

---

Unsafe

▪ Static Unsafe: Object

Type declaration

Name	Type
fromField	(x: Field) => UInt8

Defined in

lib/int.ts:1320

---

_isStruct

▪ Static _isStruct: true

Inherited from

Struct({ value: Field, })._isStruct

Defined in

lib/circuit-value.ts:382

---

empty

▪ Static empty: () => { value: Field = Field }

Type declaration

▸ (): Object

Returns

Object

Name	Type
value	Field

Inherited from

Struct({ value: Field, }).empty

Defined in

lib/circuit-value.ts:391

---

fromFields

▪ Static fromFields: (fields: Field[]) => { value: Field = Field }

Type declaration

▸ (fields): Object

A function that returns an element of type T from the given provable data.

Important: For any element of type T, this function is the reverse operation of calling toFields method on an element of type T.

Parameters

Name	Type	Description
fields	Field[]	an array of Field elements describing the provable data of the new T element.

Returns

Object

An element of type T generated from the given provable data.

Name	Type
value	Field

Inherited from

Struct({ value: Field, }).fromFields

Defined in

snarky.d.ts:138

---

fromJSON

▪ Static fromJSON: (x: { value: string = Field }) => { value: Field = Field }

Type declaration

▸ (x): Object

Parameters

Name	Type	Default value
x	Object	undefined
x.value	string	Field

Returns

Object

Name	Type
value	Field

Inherited from

Struct({ value: Field, }).fromJSON

Defined in

lib/circuit-value.ts:390

---

toAuxiliary

▪ Static toAuxiliary: (value?: { value: Field = Field }) => any[]

Type declaration

▸ (value?): any[]

A function that takes value (optional), an element of type T, as argument and returns an array of any type that make up the "auxiliary" (non-provable) data of value. As any element of the interface ProvablePure<T> includes no "auxiliary" data by definition, this function always returns a default value.

Parameters

Name	Type	Default value	Description
value?	Object	undefined	the element of type T to generate the auxiliary data array from, optional. If not provided, a default value for auxiliary data is returned.
value.value	Field	Field	-

Returns

any[]

An empty array, as any element of the interface ProvablePure<T> includes no "auxiliary" data by definition.

Inherited from

Struct({ value: Field, }).toAuxiliary

Defined in

snarky.d.ts:127

---

toFields

▪ Static toFields: (value: { value: Field = Field }) => Field[]

Type declaration

▸ (value): Field[]

A function that takes value, an element of type T, as argument and returns an array of Field elements that make up the provable data of value.

Parameters

Name	Type	Default value	Description
value	Object	undefined	the element of type T to generate the Field array from.
value.value	Field	Field	-

Returns

Field[]

A Field array describing how this T element is made up of Field elements.

Inherited from

Struct({ value: Field, }).toFields

Defined in

snarky.d.ts:117

---

toJSON

▪ Static toJSON: (x: { value: Field = Field }) => { value: string = Field }

Type declaration

▸ (x): Object

Parameters

Name	Type	Default value
x	Object	undefined
x.value	Field	Field

Returns

Object

Name	Type
value	string

Inherited from

Struct({ value: Field, }).toJSON

Defined in

lib/circuit-value.ts:389

Methods

add

▸ add(y): UInt8

Add a UInt8 to another UInt8 without allowing overflow.

Parameters

Name	Type
y	number | bigint | UInt8

Returns

UInt8

Example

const x = UInt8.from(3);
const sum = x.add(5);
sum.assertEquals(8);

Throws

if the result is greater than 255.

Defined in

lib/int.ts:1344

---

assertEquals

▸ assertEquals(y, message?): void

Assert that this UInt8 is equal another UInt8 value.

Important: If an assertion fails, the code throws an error.

Parameters

Name	Type	Description
y	number | bigint | UInt8	the UInt8 value to compare & assert with this UInt8.
message?	string	-

Returns

void

Defined in

lib/int.ts:1598

---

assertGreaterThan

▸ assertGreaterThan(y, message?): void

Assert that this UInt8 is greater than another UInt8 value.

Important: If an assertion fails, the code throws an error.

Parameters

Name	Type	Description
y	number | bigint | UInt8	the UInt8 value to compare & assert with this UInt8.
message?	string	-

Returns

void

Defined in

lib/int.ts:1574

---

assertGreaterThanOrEqual

▸ assertGreaterThanOrEqual(y, message?): void

Assert that this UInt8 is greater than or equal to another UInt8 value.

Important: If an assertion fails, the code throws an error.

Parameters

Name	Type	Description
y	UInt8	the UInt8 value to compare & assert with this UInt8.
message?	string	-

Returns

void

Defined in

lib/int.ts:1586

---

assertLessThan

▸ assertLessThan(y, message?): void

Assert that this UInt8 is less than another UInt8 value.

Important: If an assertion fails, the code throws an error.

Parameters

Name	Type	Description
y	number | bigint | UInt8	the UInt8 value to compare & assert with this UInt8.
message?	string	-

Returns

void

Defined in

lib/int.ts:1494

---

assertLessThanOrEqual

▸ assertLessThanOrEqual(y, message?): void

Assert that this UInt8 is less than or equal to another UInt8 value.

Important: If an assertion fails, the code throws an error.

Parameters

Name	Type	Description
y	number | bigint | UInt8	the UInt8 value to compare & assert with this UInt8.
message?	string	-

Returns

void

Defined in

lib/int.ts:1518

---

div

▸ div(y): UInt8

Divide a UInt8 by another UInt8. This is integer division that rounds down.

Parameters

Name	Type
y	number | bigint | UInt8

Returns

UInt8

Example

const x = UInt8.from(7);
const quotient = x.div(2);
quotient.assertEquals(3);

Defined in

lib/int.ts:1397

---

divMod

▸ divMod(y): Object

Get the quotient and remainder of a UInt8 divided by another UInt8:

x == y * q + r, where 0 <= r < y.

Parameters

Name	Type	Description
y	number | bigint | UInt8	a UInt8 to get the quotient and remainder of another UInt8.

Returns

Object

The quotient q and remainder r.

Name	Type
quotient	UInt8
remainder	UInt8

Defined in

lib/int.ts:1424

---

greaterThan

▸ greaterThan(y): Bool

Check if this UInt8 is greater than another UInt8. Returns a Bool.

Parameters

Name	Type
y	number | bigint | UInt8

Returns

Bool

Example

// 5 > 3
UInt8.from(5).greaterThan(3);

Defined in

lib/int.ts:1548

---

greaterThanOrEqual

▸ greaterThanOrEqual(y): Bool

Check if this UInt8 is greater than or equal another UInt8 value. Returns a Bool.

Parameters

Name	Type
y	number | bigint | UInt8

Returns

Bool

Example

// 3 >= 3
UInt8.from(3).greaterThanOrEqual(3);

Defined in

lib/int.ts:1562

---

lessThan

▸ lessThan(y): Bool

Check if this UInt8 is less than another UInt8 value. Returns a Bool.

Parameters

Name	Type
y	number | bigint | UInt8

Returns

Bool

Example

UInt8.from(2).lessThan(UInt8.from(3));

Defined in

lib/int.ts:1478

---

lessThanOrEqual

▸ lessThanOrEqual(y): Bool

Check if this UInt8 is less than or equal to another UInt8 value. Returns a Bool.

Parameters

Name	Type
y	number | bigint | UInt8

Returns

Bool

Example

UInt8.from(3).lessThanOrEqual(UInt8.from(5));

Defined in

lib/int.ts:1461

---

mod

▸ mod(y): UInt8

Get the remainder a UInt8 of division of another UInt8.

Parameters

Name	Type
y	number | bigint | UInt8

Returns

UInt8

Example

const x = UInt8.from(50);
const mod = x.mod(30);
mod.assertEquals(20);

Defined in

lib/int.ts:1411

---

mul

▸ mul(y): UInt8

Multiply a UInt8 by another UInt8 without allowing overflow.

Parameters

Name	Type
y	number | bigint | UInt8

Returns

UInt8

Example

const x = UInt8.from(3);
const product = x.mul(5);
product.assertEquals(15);

Throws

if the result is greater than 255.

Defined in

lib/int.ts:1380

---

sub

▸ sub(y): UInt8

Subtract a UInt8 from another UInt8 without allowing underflow.

Parameters

Name	Type
y	number | bigint | UInt8

Returns

UInt8

Example

const x = UInt8.from(8);
const difference = x.sub(5);
difference.assertEquals(3);

Throws

if the result is less than 0.

Defined in

lib/int.ts:1362

---

toBigInt

▸ toBigInt(): bigint

Serialize the UInt8 to a bigint.

Warning: This operation is not provable.

Returns

bigint

Defined in

lib/int.ts:1626

---

toNumber

▸ toNumber(): number

Serialize the UInt8 to a number.

Warning: This operation is not provable.

Returns

number

Defined in

lib/int.ts:1617

---

toString

▸ toString(): string

Serialize the UInt8 to a string, e.g. for printing.

Warning: This operation is not provable.

Returns

string

Defined in

lib/int.ts:1608

---

toUInt32

▸ toUInt32(): UInt32

Turns a UInt8 into a UInt32.

Returns

UInt32

Defined in

lib/int.ts:1646

---

toUInt64

▸ toUInt64(): UInt64

Turns a UInt8 into a UInt64.

Returns

UInt64

Defined in

lib/int.ts:1653

---

MAXINT

▸ Static MAXINT(): UInt8

Creates a UInt8 with a value of 255.

Returns

UInt8

Defined in

lib/int.ts:1660

---

check

▸ Static check(x): void

check for UInt8. Proves that the input is in the [0, 255] range.

Parameters

Name	Type
x	Field | { value: Field }

Returns

void

Overrides

Struct({ value: Field, }).check

Defined in

lib/int.ts:1634

---

checkConstant

▸ Static Private checkConstant(x): void

Parameters

Name	Type
x	Field

Returns

void

Defined in

lib/int.ts:1678

---

from

▸ Static from(x): UInt8

Creates a new UInt8.

Parameters

Name	Type
x	number | bigint | Field | UInt64 | UInt32 | UInt8

Returns

UInt8

Defined in

lib/int.ts:1667

---

sizeInFields

▸ Static sizeInFields(): number

Return the size of the T type in terms of Field type, as Field is the primitive type.

Warning: This function returns a number, so you cannot use it to prove something on chain. You can use it during debugging or to understand the memory complexity of some type.

Returns

number

A number representing the size of the T type in terms of Field type.

Inherited from

Struct({ value: Field, }).sizeInFields

Defined in

snarky.d.ts:147

---

toInput

▸ Static toInput(x): HashInput

Parameters

Name	Type
x	Object
x.value	Field

Returns

HashInput

Overrides

Struct({ value: Field, }).toInput

Defined in

lib/int.ts:1639