# Core > Shared utilities for Angular DevKit. # Exception # Json ## Schema ### SchemaValidatorResult ``` export interface SchemaValidatorResult { success: boolean; errors?: string[]; } ``` ### SchemaValidator ``` export interface SchemaValidator { (data: any): Observable; } ``` ### SchemaFormatter ``` export interface SchemaFormatter { readonly async: boolean; validate(data: any): boolean | Observable; } ``` ### SchemaRegistry ``` export interface SchemaRegistry { compile(schema: Object): Observable; addFormat(name: string, formatter: SchemaFormatter): void; } ``` ### CoreSchemaRegistry `SchemaRegistry` implementation using https://github.com/epoberezkin/ajv. Constructor accepts object containing `SchemaFormatter` that will be added automatically. ``` export class CoreSchemaRegistry implements SchemaRegistry { constructor(formats: { [name: string]: SchemaFormatter} = {}) {} } ``` # Logger # Utils # Virtual FS