Add ESM build

.npmignore

@@ -0,0 +1,5 @@
+.gitattributes
+.github
+scripts
+test
+**/*.test-d.ts

index.mjs

@@ -0,0 +1,284 @@
+'use strict'
+
+import { dequal as deepEqual } from 'dequal'
+
+const jsonSchemaRefSymbol = Symbol.for('json-schema-ref')
+
+class RefResolver {
+  #schemas
+  #derefSchemas
+  #insertRefSymbol
+  #allowEqualDuplicates
+  #cloneSchemaWithoutRefs
+
+  constructor (opts = {}) {
+    this.#schemas = {}
+    this.#derefSchemas = {}
+    this.#insertRefSymbol = opts.insertRefSymbol ?? false
+    this.#allowEqualDuplicates = opts.allowEqualDuplicates ?? true
+    this.#cloneSchemaWithoutRefs = opts.cloneSchemaWithoutRefs ?? false
+  }
+
+  addSchema (schema, rootSchemaId, isRootSchema = true) {
+    if (isRootSchema) {
+      if (schema.$id !== undefined && schema.$id.charAt(0) !== '#') {
+        // Schema has an $id that is not an anchor
+        rootSchemaId = schema.$id
+      } else {
+        // Schema has no $id or $id is an anchor
+        this.#insertSchemaBySchemaId(schema, rootSchemaId)
+      }
+    }
+
+    const schemaId = schema.$id
+    if (schemaId !== undefined && typeof schemaId === 'string') {
+      if (schemaId.charAt(0) === '#') {
+        this.#insertSchemaByAnchor(schema, rootSchemaId, schemaId)
+      } else {
+        this.#insertSchemaBySchemaId(schema, schemaId)
+        rootSchemaId = schemaId
+      }
+    }
+
+    const ref = schema.$ref
+    if (ref !== undefined && typeof ref === 'string') {
+      const { refSchemaId, refJsonPointer } = this.#parseSchemaRef(ref, rootSchemaId)
+      this.#schemas[rootSchemaId].refs.push({
+        schemaId: refSchemaId,
+        jsonPointer: refJsonPointer
+      })
+    }
+
+    for (const key in schema) {
+      if (typeof schema[key] === 'object' && schema[key] !== null) {
+        this.addSchema(schema[key], rootSchemaId, false)
+      }
+    }
+  }
+
+  getSchema (schemaId, jsonPointer = '#') {
+    const schema = this.#schemas[schemaId]
+    if (schema === undefined) {
+      throw new Error(
+        `Cannot resolve ref "${schemaId}${jsonPointer}". Schema with id "${schemaId}" is not found.`
+      )
+    }
+    if (schema.anchors[jsonPointer] !== undefined) {
+      return schema.anchors[jsonPointer]
+    }
+    return getDataByJSONPointer(schema.schema, jsonPointer)
+  }
+
+  hasSchema (schemaId) {
+    return this.#schemas[schemaId] !== undefined
+  }
+
+  getSchemaRefs (schemaId) {
+    const schema = this.#schemas[schemaId]
+    if (schema === undefined) {
+      throw new Error(`Schema with id "${schemaId}" is not found.`)
+    }
+    return schema.refs
+  }
+
+  getSchemaDependencies (schemaId, dependencies = {}) {
+    const schema = this.#schemas[schemaId]
+
+    for (const ref of schema.refs) {
+      const dependencySchemaId = ref.schemaId
+      if (
+        dependencySchemaId === schemaId ||
+        dependencies[dependencySchemaId] !== undefined
+      ) continue
+
+      dependencies[dependencySchemaId] = this.getSchema(dependencySchemaId)
+      this.getSchemaDependencies(dependencySchemaId, dependencies)
+    }
+
+    return dependencies
+  }
+
+  derefSchema (schemaId) {
+    if (this.#derefSchemas[schemaId] !== undefined) return
+
+    const schema = this.#schemas[schemaId]
+    if (schema === undefined) {
+      throw new Error(`Schema with id "${schemaId}" is not found.`)
+    }
+
+    if (!this.#cloneSchemaWithoutRefs && schema.refs.length === 0) {
+      this.#derefSchemas[schemaId] = {
+        schema: schema.schema,
+        anchors: schema.anchors
+      }
+    }
+
+    const refs = []
+    this.#addDerefSchema(schema.schema, schemaId, true, refs)
+
+    const dependencies = this.getSchemaDependencies(schemaId)
+    for (const schemaId in dependencies) {
+      const schema = dependencies[schemaId]
+      this.#addDerefSchema(schema, schemaId, true, refs)
+    }
+
+    for (const ref of refs) {
+      const {
+        refSchemaId,
+        refJsonPointer
+      } = this.#parseSchemaRef(ref.ref, ref.sourceSchemaId)
+
+      const targetSchema = this.getDerefSchema(refSchemaId, refJsonPointer)
+      if (targetSchema === null) {
+        throw new Error(
+          `Cannot resolve ref "${ref.ref}". Ref "${refJsonPointer}" is not found in schema "${refSchemaId}".`
+        )
+      }
+
+      ref.targetSchema = targetSchema
+      ref.targetSchemaId = refSchemaId
+    }
+
+    for (const ref of refs) {
+      this.#resolveRef(ref, refs)
+    }
+  }
+
+  getDerefSchema (schemaId, jsonPointer = '#') {
+    let derefSchema = this.#derefSchemas[schemaId]
+    if (derefSchema === undefined) {
+      this.derefSchema(schemaId)
+      derefSchema = this.#derefSchemas[schemaId]
+    }
+    if (derefSchema.anchors[jsonPointer] !== undefined) {
+      return derefSchema.anchors[jsonPointer]
+    }
+    return getDataByJSONPointer(derefSchema.schema, jsonPointer)
+  }
+
+  #parseSchemaRef (ref, schemaId) {
+    const sharpIndex = ref.indexOf('#')
+    if (sharpIndex === -1) {
+      return { refSchemaId: ref, refJsonPointer: '#' }
+    }
+    if (sharpIndex === 0) {
+      return { refSchemaId: schemaId, refJsonPointer: ref }
+    }
+    return {
+      refSchemaId: ref.slice(0, sharpIndex),
+      refJsonPointer: ref.slice(sharpIndex)
+    }
+  }
+
+  #addDerefSchema (schema, rootSchemaId, isRootSchema, refs = []) {
+    const derefSchema = Array.isArray(schema) ? [...schema] : { ...schema }
+
+    if (isRootSchema) {
+      if (schema.$id !== undefined && schema.$id.charAt(0) !== '#') {
+        // Schema has an $id that is not an anchor
+        rootSchemaId = schema.$id
+      } else {
+        // Schema has no $id or $id is an anchor
+        this.#insertDerefSchemaBySchemaId(derefSchema, rootSchemaId)
+      }
+    }
+
+    const schemaId = derefSchema.$id
+    if (schemaId !== undefined && typeof schemaId === 'string') {
+      if (schemaId.charAt(0) === '#') {
+        this.#insertDerefSchemaByAnchor(derefSchema, rootSchemaId, schemaId)
+      } else {
+        this.#insertDerefSchemaBySchemaId(derefSchema, schemaId)
+        rootSchemaId = schemaId
+      }
+    }
+
+    if (derefSchema.$ref !== undefined) {
+      refs.push({
+        ref: derefSchema.$ref,
+        sourceSchemaId: rootSchemaId,
+        sourceSchema: derefSchema
+      })
+    }
+
+    for (const key in derefSchema) {
+      const value = derefSchema[key]
+      if (typeof value === 'object' && value !== null) {
+        derefSchema[key] = this.#addDerefSchema(value, rootSchemaId, false, refs)
+      }
+    }
+
+    return derefSchema
+  }
+
+  #resolveRef (ref, refs) {
+    const { sourceSchema, targetSchema } = ref
+
+    if (!sourceSchema.$ref) return
+    if (this.#insertRefSymbol) {
+      sourceSchema[jsonSchemaRefSymbol] = sourceSchema.$ref
+    }
+
+    delete sourceSchema.$ref
+
+    if (targetSchema.$ref) {
+      const targetSchemaRef = refs.find(ref => ref.sourceSchema === targetSchema)
+      this.#resolveRef(targetSchemaRef, refs)
+    }
+    for (const key in targetSchema) {
+      if (key === '$id') continue
+      if (sourceSchema[key] !== undefined) {
+        if (deepEqual(sourceSchema[key], targetSchema[key])) continue
+        throw new Error(
+          `Cannot resolve ref "${ref.ref}". Property "${key}" is already exist in schema "${ref.sourceSchemaId}".`
+        )
+      }
+      sourceSchema[key] = targetSchema[key]
+    }
+    ref.isResolved = true
+  }
+
+  #insertSchemaBySchemaId (schema, schemaId) {
+    const foundSchema = this.#schemas[schemaId]
+    if (foundSchema !== undefined) {
+      if (this.#allowEqualDuplicates && deepEqual(schema, foundSchema.schema)) return
+      throw new Error(`There is already another schema with id "${schemaId}".`)
+    }
+    this.#schemas[schemaId] = { schema, anchors: {}, refs: [] }
+  }
+
+  #insertSchemaByAnchor (schema, schemaId, anchor) {
+    const { anchors } = this.#schemas[schemaId]
+    if (anchors[anchor] !== undefined) {
+      throw new Error(`There is already another anchor "${anchor}" in a schema "${schemaId}".`)
+    }
+    anchors[anchor] = schema
+  }
+
+  #insertDerefSchemaBySchemaId (schema, schemaId) {
+    const foundSchema = this.#derefSchemas[schemaId]
+    if (foundSchema !== undefined) return
+
+    this.#derefSchemas[schemaId] = { schema, anchors: {} }
+  }
+
+  #insertDerefSchemaByAnchor (schema, schemaId, anchor) {
+    const { anchors } = this.#derefSchemas[schemaId]
+    anchors[anchor] = schema
+  }
+}
+
+function getDataByJSONPointer (data, jsonPointer) {
+  const parts = jsonPointer.split('/')
+  let current = data
+  for (const part of parts) {
+    if (part === '' || part === '#') continue
+    if (typeof current !== 'object' || current === null) {
+      return null
+    }
+    current = current[part]
+  }
+  return current ?? null
+}
+
+export { RefResolver }

package.json

@@ -5,15 +5,31 @@
   "main": "index.js",
   "type": "commonjs",
   "types": "types/index.d.ts",
+  "exports": {
+    ".": {
+      "import": {
+        "default": "./index.mjs",
+        "types": "./types/index.d.mts"
+      },
+      "default": {
+        "default": "./index.js",
+        "types": "./types/index.d.ts"
+      }
+    },
+    "./*": "./*"
+  },
   "scripts": {
     "lint": "eslint",
     "lint:fix": "eslint --fix",
     "test:unit": "c8 --100 node --test",
     "test:typescript": "tsd",
-    "test": "npm run lint && npm run test:unit && npm run test:typescript"
+    "test": "npm run lint && npm run test:unit && npm run test:typescript",
+    "build": "node ./scripts/generate-esm.mjs",
+    "version": "npm run build"
   },
   "precommit": [
     "lint",
+    "build",
     "test"
   ],
   "repository": {

scripts/generate-esm.mjs

@@ -0,0 +1,40 @@
+import fs from 'node:fs'
+
+const CWD = new URL('../', import.meta.url)
+
+// list of all inputs/outputs, with replacements
+const SOURCE_FILES = [
+  {
+    source: './index.js',
+    types: './types/index.d.ts',
+    replacements: [
+      [/const\s+([^=]+)=\s*require\(([^)]+)\)/g, (_, spec, moduleName) => {
+        return `import ${spec.trim().replace(/:\s*/g, ' as ')} from ${moduleName.trim()}`
+      }],
+      [/module\.exports\s*=\s*({[^}]+})/, 'export $1'],
+    ]
+  }
+]
+
+// Build script
+for (const { source, types, replacements } of SOURCE_FILES) {
+  // replace
+  let output = fs.readFileSync(new URL(source, CWD), 'utf8')
+  for (const [search, replaceValue] of replacements) {
+    output = output.replace(search, replaceValue)
+  }
+
+  // verify
+  if (output.includes('require(')) {
+    throw new Error('Could not convert all require() statements')
+  }
+  if (output.includes('module.exports')) {
+    throw new Error('Could not convert module.exports statement')
+  }
+
+  // write source
+  fs.writeFileSync(new URL(source.replace(/\.js$/, '.mjs'), CWD), output)
+
+  // write types
+  fs.copyFileSync(new URL(types, CWD), new URL(types.replace(/\.d\.ts$/, '.d.mts'), CWD))
+}