Class: DataSchema

The DataSchema class abstracts UniRep data into a JavaScript object. This class can be used to encode and decode attestation data, and build attestations that are ready to be submitted to the UniRep smart contract.

Example

import { Attestation, DataSchema, SchemaField } from '@unirep/core'

const schema: SchemaField[] = [
  {name: 'posRep', type: 'uint64', updateBy: 'sum',},
  {name: 'negRep', type: 'uint64', updateBy: 'sum',},
  {name: 'graffiti', type: 'uint205', updateBy: 'replace',},
  {name: 'postCount', type: 'uint49', updateBy: 'sum',},
  {name: 'commentCount', type: 'uint49', updateBy: 'sum',},
  {name: 'voteCount', type: 'uint49', updateBy: 'sum',},
]

const d = new DataSchema(schema)

Constructors

constructor

• new DataSchema(schema, config?)

Parameters

Name	Type	Default value
schema	SchemaField[]	undefined
config	CircuitConfig	CircuitConfig.default

Defined in

packages/core/src/DataSchema.ts:55

Properties

config

• config: CircuitConfig

Defined in

packages/core/src/DataSchema.ts:53

---

schema

• schema: any[]

Defined in

packages/core/src/DataSchema.ts:52

Methods

buildAttestation

▸ buildAttestation(change): Attestation

Build an Attestation object to be used for a UniRep contract

Parameters

Name	Type	Description
change	Object	The data change. If it is sum field, the data will be changed by addition. If it is replacement field, the data will be changed by replacement.
change.name	string	-
change.val	bigint	-

Returns

Attestation

The attestation object will be submitted to the Unirep contract.

Example

Sum field

// 10 will be added to the 'posRep' field in the user data
const sumChange = { name: 'posRep', val: BigInt(10) }
const sumAttestation: Attestation = d.buildAttestation(sumChange)

Replacement field

// 20 will replace the current value in the 'graffiti' field in user data
const replacementChange = { name: 'graffiti', val: BigInt(20) }
const replacementAttestation: Attestation = d.buildAttestation(replacementChange)

Defined in

packages/core/src/DataSchema.ts:168

---

buildAttestations

▸ buildAttestations(changes): Attestation[]

Build multiple Attestation objects to be used for a UniRep contract

Parameters

Name	Type	Description
changes	{ name: string ; val: bigint }[]	The array of data change.

Returns

Attestation[]

The array of attestations will be submitted to the Unirep contract.

Example

// Multiple attestations can be built using `buildAttestations()`
const changes = [
  { name: 'posRep', val: BigInt(10) },
  { name: 'negRep', val: BigInt(10) },
  { name: 'negRep', val: BigInt(20) },
  { name: 'graffiti', val: BigInt(30) },
]

//Returns two `Attestation` objects: 'posRep' and 'negRep' attestations are combined into one attestation
const attestations: Attestation[] = d.buildAttestations(changes)

Defined in

packages/core/src/DataSchema.ts:209

---

parseData

▸ parseData(data): any

Parse encoded schema, producing a dictionary of user-defined field names and attestation values

Parameters

Name	Type	Description
data	bigint[]	The raw data appended to the Unirep contract.

Returns

any

The names of the data and its values.

Example

// JS literal representing emitted data from a UniRep contract
const data = [
  553402322211286548490n,
  0n,
  0n,
  0n,
  205688069665150755269371147819668813122841983204197482918576158n,
  0n
]

const parsedData = d.parseData(data)
// Result:
// parsedData = {
//   posRep: 10n,
//   negRep: 30n,
//   graffiti: 30n,
//   postCount: 0n,
//   commentCount: 0n,
//   voteCount: 0n
// }

Defined in

packages/core/src/DataSchema.ts:276

---

parseSchema

▸ parseSchema(schema): any[]

Verify a user-defined data schema

Parameters

Name	Type	Description
schema	SchemaField[]	The array of SchemaField

Returns

any[]

{
  ...schema: SchemaField, // exploded `SchemaField` fields
  dataIndex: number,
  offset: number, // bit offset in attester change
  bits: number // bits allocated
}

Defined in

packages/core/src/DataSchema.ts:73