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Constraint

Represents a single constraint that modifies a Rule.

Constraints are conditions that must be satisfied for a rule to be applicable. All constraints in a rule's constraint list must be met (AND logic). Constraints can use predefined types from the PD-REL vocabulary or custom URIs for domain-specific requirements.

Per the PD-REL v1.0 specification: "A condition that must be met for a Rule to be active. Constraints define the 'if' conditions of a policy (e.g., 'if the time is after X,' 'if the user holds token Y')."

Examples​

// Time-based constraint limiting access to a specific period
const timeConstraint: Constraint = {
  type: 'TIME_PERIOD',
  value: {
    start: 1704067200, // January 1, 2024 00:00 UTC
    end: 1735689599    // December 31, 2024 23:59:59 UTC
  }
};

// Token-gated constraint requiring NFT ownership
const tokenConstraint: Constraint = {
  type: 'TOKEN_GATED',
  value: {
    chainId: 1,
    contractAddress: '0x1234...',
    minBalance: 1
  }
};

// Custom constraint using a URI
const customConstraint: Constraint = {
  type: 'https://example.com/constraints/verified-identity',
  value: { verificationLevel: 'KYC_FULL' }
};

Definition​

interface Constraint {
  /**
   * The type of constraint, from the core vocabulary or a custom URI.  Use predefined types from ConstraintType for standard constraints, or provide a fully-qualified URI for custom constraint types.
   */
  type: string;
  /**
   * The value of the constraint, which can be a primitive or an object.  The structure of the value depends on the constraint type: - TIME_PERIOD: `{ start: number, end: number }` (Unix timestamps) - USAGE_COUNT: `number` (maximum usage count) - TOKEN_GATED: `{ chainId: number, contractAddress: string, minBalance: number }` - SPATIAL: `string` (location identifier) or complex object - Custom types: Any valid JSON value
   */
  value: any;
}

Properties​

type​

The type of constraint, from the core vocabulary or a custom URI.

Use predefined types from ConstraintType for standard constraints, or provide a fully-qualified URI for custom constraint types.

Type: string

Examples​

type: 'TIME_PERIOD' // Predefined type
type: 'https://myorg.com/constraints/age-restriction' // Custom URI

value​

The value of the constraint, which can be a primitive or an object.

The structure of the value depends on the constraint type:

  • TIME_PERIOD: { start: number, end: number } (Unix timestamps)
  • USAGE_COUNT: number (maximum usage count)
  • TOKEN_GATED: { chainId: number, contractAddress: string, minBalance: number }
  • SPATIAL: string (location identifier) or complex object
  • Custom types: Any valid JSON value

Type: any

See Also​

  • Rule for how constraints are applied to rules

Since​

Version 1.0.0