feat: add hasSchema method

index.js

@@ -41,6 +41,10 @@ class RefResolver {
     return getDataByJSONPointer(schema.schema, jsonPointer)
   }
 
+  hasSchema (schemaId) {
+    return this.#schemas[schemaId] !== undefined
+  }
+
   getSchemaRefs (schemaId) {
     const schema = this.#schemas[schemaId]
     if (schema === undefined) {

test/has-schema.test.js

@@ -0,0 +1,28 @@
+'use strict'
+
+const assert = require('node:assert/strict')
+const { test } = require('node:test')
+const { RefResolver } = require('../index.js')
+
+test('should return true if schema exists', () => {
+  const refResolver = new RefResolver()
+
+  const schemaId = 'schemaId'
+  const schema = {
+    $id: 'schemaId',
+    type: 'object',
+    properties: {
+      foo: { type: 'string' }
+    }
+  }
+  refResolver.addSchema(schema)
+
+  const hasSchema = refResolver.hasSchema(schemaId)
+  assert.strictEqual(hasSchema, true)
+})
+
+test('should return false if schema does not exist', () => {
+  const refResolver = new RefResolver()
+  const hasSchema = refResolver.hasSchema('schemaId')
+  assert.strictEqual(hasSchema, false)
+})

types/index.d.ts

@@ -27,6 +27,13 @@ declare class RefResolver {
    */
   getSchema(schemaId: string, jsonPointer?: string): any | null;
 
+  /**
+   * Returns true if the schema by the given schema id is added to the resolver.
+   * @param {string} schemaId - The schema id of the schema to be checked.
+   * @returns {boolean} True if the schema by the given schema id is added to the resolver.
+   */
+  hasSchema(schemaId: string): boolean;
+
   /**
    * Returns the schema references of the schema by the given schema id.
    * @param {string} schemaId - The schema id of the schema whose references are to be returned.

types/index.test-d.ts

@@ -11,6 +11,8 @@ expectType<void>(resolver.addSchema({}, 'schemaId'))
 expectType<any | null>(resolver.getSchema('schemaId'))
 expectType<any | null>(resolver.getSchema('schemaId', 'jsonPointer'))
 
+expectType<boolean>(resolver.hasSchema('schemaId'))
+
 expectType<{ schemaId: string; jsonPointer: string }[]>(resolver.getSchemaRefs('schemaId'))
 
 expectType<{ [key: string]: any }>(resolver.getSchemaDependencies('schemaId'))