Meta-Schema Configuration

Instance-Level Configuration

Configure meta-schema behavior when creating a @jetio/validator instance.


interface ValidatorOptions {
  validateSchema?: boolean; // Default: true  — enable schema validation
  metaSchema: string; // Default: ''    — default meta-schema for schemas without $schema
}

Enable validation with a default


const jetValidator = new JetValidator({
  validateSchema: true,
  metaSchema: "draft-07",
});
loadDraft07(jetValidator);
 
const schema = { type: "string" }; // no $schema keyword
jetValidator.validateSchema(schema); // validates against Draft-07

Disable validation for production


const jetValidator = new JetValidator({
  validateSchema: false, // skip validation for performance
});
 
// No need to load meta-schemas
const validate = jetValidator.compile({
  type: "object",
  properties: { name: { type: "string" } },
});

Compilation-Level Configuration

Override instance configuration per compile call.


const jetValidator = new JetValidator({
  validateSchema: true,
  metaSchema: "draft-07", // instance default
});
loadAllMetaSchemas(jetValidator);
 
// Instance default (Draft-07)
const validate1 = jetValidator.compile(schema);
 
// Override to Draft 2020-12
const validate2 = jetValidator.compile(schema, {
  metaSchema: "draft/2020-12",
});
 
// Disable validation for this compilation
const validate3 = jetValidator.compile(schema, {
  validateSchema: false,
});

Per-schema strategy — strict for critical schemas, lenient for internal ones:


const userValidator = jetValidator.compile(userSchema, {
  validateSchema: true,
  metaSchema: "draft/2020-12",
  strict: true,
  allErrors: true,
});
 
const internalValidator = jetValidator.compile(internalSchema, {
  validateSchema: false,
  coerceTypes: true,
});

Built-in Aliases

@jetio/validator provides short aliases for meta-schema URIs to cut verbosity. They work everywhere a meta-schema is accepted — the constructor, validateSchema, compile, and compileAsync.

Short Alias	Full URI
`draft-06`	`https://json-schema.org/draft-06/schema`
`draft-07`	`https://json-schema.org/draft-07/schema`
`draft/2019-09`	`https://json-schema.org/draft/2019-09/schema`
`draft/2020-12`	`https://json-schema.org/draft/2020-12/schema`


// These are equivalent:
jetValidator.validateSchema(schema, {
  metaSchema: "https://json-schema.org/draft-07/schema",
});
jetValidator.validateSchema(schema, {
  metaSchema: "draft-07", // resolved internally to the full URI
});

API Reference

Adding meta-schemas

Method	Signature	Returns	Description
`addMetaSchema`	`(schema: SchemaDefinition, key?: string)`	`this`	Register a meta-schema

Validating schemas

Method	Signature	Returns	Description
`validateSchemaSync`	`(schema: SchemaDefinition, options?: ValidatorOptions)`	`ValidationResult`	Validate and compile synchronously with full control
`validateSchemaAsync`	`(schema: SchemaDefinition, options?: ValidatorOptions)`	`Promise<ValidationResult>`	Validate and compile asynchronously, loading external meta-schemas

Configuration options

Option	Type	Default	Description
`validateSchema`	`boolean`	`true`	Enable schema validation before compilation
`metaSchema`	`string`	`''`	Default meta-schema URI or alias

CLI

Command	Description
`jet-meta load <version> [dir]`	Download meta-schemas to a directory

Loader functions (auto-generated)

Function	Description
`loadDraft06(jetValidator)`	Load JSON Schema Draft-06 meta-schemas
`loadDraft07(jetValidator)`	Load JSON Schema Draft-07 meta-schemas
`loadDraft201909(jetValidator)`	Load JSON Schema Draft 2019-09 meta-schemas
`loadDraft202012(jetValidator)`	Load JSON Schema Draft 2020-12 meta-schemas
`loadAllMetaSchemas(jetValidator)`	Load all downloaded meta-schemas