refactor: compare schemas with same schema id

Author: ivan-tymoshenko

package.json

@@ -52,6 +52,7 @@
     "@fastify/deepmerge": "^1.0.0",
     "ajv": "^8.10.0",
     "ajv-formats": "^2.1.1",
+    "fast-deep-equal": "^3.1.3",
     "fast-uri": "^2.1.0",
     "rfdc": "^1.2.0"
   },

ref-resolver.js

@@ -1,45 +1,67 @@
 'use strict'
 
+const deepEqual = require('fast-deep-equal')
+
 class RefResolver {
   constructor () {
-    this.refs = {}
+    this.schemas = {}
   }
 
   addSchema (schema, schemaKey) {
-    if (schema === null) return
-
     if (schema.$id !== undefined && schema.$id.charAt(0) !== '#') {
       schemaKey = schema.$id
     }
-
-    this.refs[schemaKey] = { schema, anchors: {} }
-    this.resolveSchema(schema, schemaKey, '')
+    this.insertSchemaBySchemaId(schema, schemaKey)
+    this.insertSchemaSubschemas(schema, schemaKey)
   }
 
   getSchema (schemaReference) {
     const [schemaKey, jsonPointer] = schemaReference.split('#')
-    const schema = this.refs[schemaKey]
-
+    const schema = this.schemas[schemaKey]
     if (schema === undefined) {
       return undefined
     }
+    if (schema.anchors[jsonPointer] !== undefined) {
+      return schema.anchors[jsonPointer]
+    }
+    return getDataByJSONPointer(schema.schema, jsonPointer)
+  }
+
+  insertSchemaBySchemaId (schema, schemaId) {
+    if (
+      this.schemas[schemaId] !== undefined &&
+      !deepEqual(schema, this.schemas[schemaId].schema)
+    ) {
+      throw new Error(`There is already another schema with id ${schemaId}`)
+    }
+    this.schemas[schemaId] = { schema, anchors: {} }
+  }
 
-    return schema.anchors[jsonPointer] || getDataByJSONPointer(schema.schema, jsonPointer)
+  insertSchemaByAnchor (schema, schemaId, anchor) {
+    const { anchors } = this.schemas[schemaId]
+    if (
+      anchors[anchor] !== undefined &&
+      !deepEqual(schema, anchors[anchor])
+    ) {
+      throw new Error(`There is already another schema with id ${schemaId}#${anchor}`)
+    }
+    anchors[anchor] = schema
   }
 
-  resolveSchema (schema, schemaKey, jsonPointer) {
+  insertSchemaSubschemas (schema, rootSchemaId) {
     const schemaId = schema.$id
     if (schemaId !== undefined && typeof schemaId === 'string') {
       if (schemaId.charAt(0) === '#') {
-        this.refs[schemaKey].anchors[schemaId.slice(1)] = schema
+        const anchor = schemaId.slice(1)
+        this.insertSchemaByAnchor(schema, rootSchemaId, anchor)
       } else {
-        this.refs[schemaId] = { schema, anchors: {} }
+        this.insertSchemaBySchemaId(schema, schemaId)
       }
     }
 
     for (const key in schema) {
       if (typeof schema[key] === 'object' && schema[key] !== null) {
-        this.resolveSchema(schema[key], schemaKey, jsonPointer + '/' + key)
+        this.insertSchemaSubschemas(schema[key], rootSchemaId)
       }
     }
   }
@@ -48,15 +70,9 @@ class RefResolver {
 function getDataByJSONPointer (data, jsonPointer) {
   const parts = jsonPointer.split('/')
   let current = data
-  for (let i = 0; i < parts.length; i++) {
-    const part = parts[i]
-    if (part === '') {
-      continue
-    }
-    if (part.charAt(0) === '#') {
-      continue
-    }
-    if (current[part] === undefined) {
+  for (const part of parts) {
+    if (part === '') continue
+    if (typeof current !== 'object' || current === null) {
       return undefined
     }
     current = current[part]