Module index

Linked data validation API.

Provides a type-safe DSL for defining resource shapes with validation constraints based on the Shapes Constraint Language (SHACL). Shapes define both the expected structure and validation rules for resources, enabling compile-time type inference and runtime validation.

Shape Types

ValueShape is a discriminated union of all concrete shape types:

• BooleanShape - Booleans
• NumberShape - Numbers
• StringShape - Strings
• LocalShape - Single-valued language-tagged maps
• LocalsShape - Multi-valued language-tagged maps
• ReferenceShape - Resource IRI references
• ResourceShape - Nested resources

Defining Shapes

Define resource shapes with property constraints and value ranges:

import { resource, id, required, optional, repeatable } from '@metreeca/blue';
import { string, integer, boolean, date } from '@metreeca/blue';

const Product = resource({
  id: id(),
  name: required(string({ minLength: 1, maxLength: 100 })),
  price: required(integer({ minInclusive: 0 })),
  available: optional(boolean()),
  tags: repeatable(string()),
  releaseDate: optional(date())
});
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Validating Resources

Validate values against shapes using pattern matching on the Relay result:

import { validate } from '@metreeca/blue';

const name = validate(data, Product)({
  value: product => product.name
}); // undefined if validation fails
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Validation Modes

Beyond complete resource states, validate supports partial updates, projections, and queries:

// validate a complete resource state (default)
validate(data, Product);

// validate a partial update (null values = deletions)
validate(data, Product, { mode: "patch" });

// validate a projection model
validate(data, Product, { mode: "model" });

// validate a query with filtering and pagination
validate(data, Product, { mode: "query" });
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Custom Validators

Implement custom resource-level constraints using Validator functions. Use collect to merge multiple facets into a single canonical trace:

import { collect } from '@metreeca/blue';
import type { Trace } from '@metreeca/blue';

interface Product { minPrice?: number; maxPrice?: number; startDate?: string; endDate?: string }

function checkProduct(value: Product): Trace {
  return collect([
    value.minPrice !== undefined && value.maxPrice !== undefined
    		&& value.minPrice > value.maxPrice
      ? ["minPrice must not exceed maxPrice"]
      : [],
    value.startDate !== undefined && value.endDate !== undefined
    		&& value.startDate > value.endDate
      ? ["startDate must not follow endDate"]
      : []
  ]);
}

const Product = resource({ validators: [checkProduct] }, {
  minPrice: optional(integer()),
  maxPrice: optional(integer()),
  startDate: optional(date()),
  endDate: optional(date())
});
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