import { Schema, Validator, ValidatorResult } from 'jsonschema'; import values = require('lodash.values'); import { schemas } from './schemas'; /** * A validator for [JSON-schemas](http://json-schema.org/) */ export class SchemaValidator { private _validator: Validator; /** * Instantiates a SchemaValidator instance */ constructor() { this._validator = new Validator(); for (const schema of values(schemas)) { this._validator.addSchema(schema, schema.id); } } /** * Add a schema to the validator. All schemas and sub-schemas must be added to * the validator before the `validate` and `isValid` methods can be called with * instances of that schema. * @param schema The schema to add */ public addSchema(schema: Schema) { this._validator.addSchema(schema, schema.id); } // In order to validate a complex JS object using jsonschema, we must replace any complex // sub-types (e.g BigNumber) with a simpler string representation. Since BigNumber and other // complex types implement the `toString` method, we can stringify the object and // then parse it. The resultant object can then be checked using jsonschema. /** * Validate the JS object conforms to a specific JSON schema * @param instance JS object in question * @param schema Schema to check against * @returns The results of the validation */ public validate(instance: any, schema: Schema): ValidatorResult { const jsonSchemaCompatibleObject = JSON.parse(JSON.stringify(instance)); return this._validator.validate(jsonSchemaCompatibleObject, schema); } /** * Check whether an instance properly adheres to a JSON schema * @param instance JS object in question * @param schema Schema to check against * @returns Whether or not the instance adheres to the schema */ public isValid(instance: any, schema: Schema): boolean { const isValid = this.validate(instance, schema).errors.length === 0; return isValid; } }