diff --git a/lib/JSONAPISerializer.js b/lib/JSONAPISerializer.js
index eb80f8f..f5c37ce 100644
--- a/lib/JSONAPISerializer.js
+++ b/lib/JSONAPISerializer.js
@@ -19,7 +19,6 @@ const { validateOptions, validateDynamicTypeOptions, validateError } = require('
 
 /**
  * JSONAPISerializer class.
- *
  * @example
  * const JSONAPISerializer = require('json-api-serializer');
  *
@@ -45,10 +44,9 @@ module.exports = class JSONAPISerializer {
 
   /**
    * Register a resource with its type, schema name, and configuration options.
-   *
    * @function JSONAPISerializer#register
    * @param {string} type resource's type.
-   * @param {string|Options} [schema='default'] schema name.
+   * @param {string|Options} [schema] schema name.
    * @param {Options} [options] options.
    */
   register(type, schema, options) {
@@ -67,15 +65,14 @@ module.exports = class JSONAPISerializer {
   /**
    * Serialze input data to a JSON API compliant response.
    * Input data can be a simple object or an array of objects.
-   *
    * @see {@link http://jsonapi.org/format/#document-top-level}
    * @function JSONAPISerializer#serialize
    * @param {string|DynamicTypeOptions} type resource's type as string or a dynamic type options as object.
    * @param {object|object[]} data input data.
-   * @param {string|object} [schema='default'] resource's schema name.
+   * @param {string|object} [schema] resource's schema name.
    * @param {object} [extraData] additional data that can be used in topLevelMeta options.
    * @param {boolean} [excludeData] boolean that can be set to exclude the `data` property in serialized data.
-   * @param {object} [overrideSchemaOptions={}] additional schema options, a map of types with options to override.
+   * @param {object} [overrideSchemaOptions] additional schema options, a map of types with options to override.
    * @returns {object|object[]} serialized data.
    */
   serialize(type, data, schema, extraData, excludeData, overrideSchemaOptions = {}) {
@@ -104,7 +101,7 @@ module.exports = class JSONAPISerializer {
         data,
         included,
         extraData,
-        overrideSchemaOptions
+        overrideSchemaOptions,
       );
     } else {
       dataProperty = this.serializeResource(
@@ -113,7 +110,7 @@ module.exports = class JSONAPISerializer {
         options,
         included,
         extraData,
-        overrideSchemaOptions
+        overrideSchemaOptions,
       );
     }
 
@@ -129,15 +126,14 @@ module.exports = class JSONAPISerializer {
   /**
    * Asynchronously serialize input data to a JSON API compliant response.
    * Input data can be a simple object or an array of objects.
-   *
    * @see {@link http://jsonapi.org/format/#document-top-level}
    * @function JSONAPISerializer#serializeAsync
    * @param {string|DynamicTypeOptions} type resource's type as string or a dynamic type options as object.
    * @param {object|object[]} data input data.
-   * @param {string} [schema='default'] resource's schema name.
+   * @param {string} [schema] resource's schema name.
    * @param {object} [extraData] additional data that can be used in topLevelMeta options.
    * @param {boolean} [excludeData] boolean that can be set to exclude the `data` property in serialized data.
-   * @param {object} [overrideSchemaOptions={}] additional schema options, a map of types with options to override.
+   * @param {object} [overrideSchemaOptions] additional schema options, a map of types with options to override.
    * @returns {Promise} resolves with serialized data.
    */
   serializeAsync(type, data, schema, extraData, excludeData, overrideSchemaOptions = {}) {
@@ -164,7 +160,6 @@ module.exports = class JSONAPISerializer {
     return new Promise((resolve, reject) => {
       /**
        * Non-blocking serialization using the immediate queue.
-       *
        * @see {@link https://nodejs.org/en/docs/guides/event-loop-timers-and-nexttick/}
        */
       function next() {
@@ -184,7 +179,7 @@ module.exports = class JSONAPISerializer {
                   arrayData[i],
                   included,
                   extraData,
-                  overrideSchemaOptions
+                  overrideSchemaOptions,
                 )
               : that.serializeResource(
                   type,
@@ -192,7 +187,7 @@ module.exports = class JSONAPISerializer {
                   options,
                   included,
                   extraData,
-                  overrideSchemaOptions
+                  overrideSchemaOptions,
                 );
 
             if (serializedItem !== null) {
@@ -235,11 +230,10 @@ module.exports = class JSONAPISerializer {
   /**
    * Deserialize JSON API document data.
    * Input data can be a simple object or an array of objects.
-   *
    * @function JSONAPISerializer#deserialize
    * @param {string|DynamicTypeOptions} type resource's type as string or a dynamic type options as object.
    * @param {object} data JSON API input data.
-   * @param {string} [schema='default'] resource's schema name.
+   * @param {string} [schema] resource's schema name.
    * @returns {object} deserialized data.
    */
   deserialize(type, data, schema) {
@@ -262,7 +256,7 @@ module.exports = class JSONAPISerializer {
     if (data.data) {
       deserializedData = Array.isArray(data.data)
         ? data.data.map((resource) =>
-            this.deserializeResource(type, resource, schema, data.included)
+            this.deserializeResource(type, resource, schema, data.included),
           )
         : this.deserializeResource(type, data.data, schema, data.included);
     }
@@ -273,11 +267,10 @@ module.exports = class JSONAPISerializer {
   /**
    * Asynchronously Deserialize JSON API document data.
    * Input data can be a simple object or an array of objects.
-   *
    * @function JSONAPISerializer#deserializeAsync
    * @param {string|DynamicTypeOptions} type resource's type as string or a dynamic type options as object.
    * @param {object} data JSON API input data.
-   * @param {string} [schema='default'] resource's schema name.
+   * @param {string} [schema] resource's schema name.
    * @returns {Promise} resolves with serialized data.
    */
   deserializeAsync(type, data, schema) {
@@ -304,7 +297,6 @@ module.exports = class JSONAPISerializer {
     return new Promise((resolve, reject) => {
       /**
        * Non-blocking deserialization using the immediate queue.
-       *
        * @see {@link https://nodejs.org/en/docs/guides/event-loop-timers-and-nexttick/}
        */
       function next() {
@@ -319,7 +311,7 @@ module.exports = class JSONAPISerializer {
               type,
               arrayData[i],
               schema,
-              data.included
+              data.included,
             );
 
             deserializedData.push(deserializedItem);
@@ -340,9 +332,8 @@ module.exports = class JSONAPISerializer {
   /**
    * Serialize any error into a JSON API error document.
    * Input data can be:
-   *  - An `Error` or an array of `Error` instances.
-   *  - A JSON API error object or an array of JSON API error objects.
-   *
+   * - An `Error` or an array of `Error` instances.
+   * - A JSON API error object or an array of JSON API error objects.
    * @see {@link http://jsonapi.org/format/#errors}
    * @function JSONAPISerializer#serializeError
    * @param {Error|Error[]|object|object[]} error an Error, an array of Error, a JSON API error object, an array of JSON API error object.
@@ -359,12 +350,11 @@ module.exports = class JSONAPISerializer {
   /**
    * Deserialize a single JSON API resource.
    * Input data must be a simple object.
-   *
    * @function JSONAPISerializer#deserializeResource
    * @private
    * @param {string|DynamicTypeOptions} type resource's type as string or an object with a dynamic type resolved from data.
    * @param {object} data JSON API resource data.
-   * @param {string} [schema='default'] resource's schema name.
+   * @param {string} [schema] resource's schema name.
    * @param {Map<string, object>} included Included resources.
    * @param {string[]} lineage resource identifiers already deserialized to prevent circular references.
    * @returns {object} deserialized data.
@@ -426,7 +416,7 @@ module.exports = class JSONAPISerializer {
             set(
               deserializedData,
               (relationshipOptions && relationshipOptions.alternativeKey) || relationshipKey,
-              null
+              null,
             );
           } else {
             if ((relationshipOptions && relationshipOptions.alternativeKey) || !included) {
@@ -435,7 +425,7 @@ module.exports = class JSONAPISerializer {
                 (relationshipOptions && relationshipOptions.alternativeKey) || relationshipKey,
                 Array.isArray(relationship.data)
                   ? relationship.data.map((d) => deserializeFunction(d))
-                  : deserializeFunction(relationship.data)
+                  : deserializeFunction(relationship.data),
               );
             }
 
@@ -457,7 +447,7 @@ module.exports = class JSONAPISerializer {
                   relationshipOptions,
                   included,
                   lineageCopy,
-                  deserializeFunction
+                  deserializeFunction,
                 );
               };
 
@@ -503,7 +493,6 @@ module.exports = class JSONAPISerializer {
 
   /**
    * Deserialize included
-   *
    * @function JSONAPISerializer#deserializeIncluded
    * @private
    * @param {string} type resource's type as string or an object with a dynamic type resolved from data.
@@ -516,7 +505,7 @@ module.exports = class JSONAPISerializer {
    */
   deserializeIncluded(type, id, relationshipOpts, included, lineage, deserializeFunction) {
     const includedResource = included.find(
-      (resource) => resource.type === type && resource.id === id
+      (resource) => resource.type === type && resource.id === id,
     );
 
     if (!includedResource) {
@@ -532,13 +521,12 @@ module.exports = class JSONAPISerializer {
       includedResource,
       relationshipOpts.schema,
       included,
-      lineage
+      lineage,
     );
   }
 
   /**
    * Serialize resource objects.
-   *
    * @see {@link http://jsonapi.org/format/#document-resource-objects}
    * @function JSONAPISerializer#serializeDocument
    * @private
@@ -547,7 +535,7 @@ module.exports = class JSONAPISerializer {
    * @param {Options} options resource's configuration options.
    * @param {Map<string, object>} [included] Included resources.
    * @param {object} [extraData] additional data.
-   * @param {object} [overrideSchemaOptions={}] additional schema options, a map of types with options to override.
+   * @param {object} [overrideSchemaOptions] additional schema options, a map of types with options to override.
    * @returns {object|object[]} serialized data.
    */
   serializeResource(type, data, options, included, extraData, overrideSchemaOptions = {}) {
@@ -558,7 +546,7 @@ module.exports = class JSONAPISerializer {
 
     if (Array.isArray(data)) {
       return data.map((d) =>
-        this.serializeResource(type, d, options, included, extraData, overrideSchemaOptions)
+        this.serializeResource(type, d, options, included, extraData, overrideSchemaOptions),
       );
     }
 
@@ -575,7 +563,7 @@ module.exports = class JSONAPISerializer {
         options,
         included,
         extraData,
-        overrideSchemaOptions
+        overrideSchemaOptions,
       ),
       meta: this.processOptionsValues(data, extraData, options.meta),
       links: this.processOptionsValues(data, extraData, options.links),
@@ -584,7 +572,6 @@ module.exports = class JSONAPISerializer {
 
   /**
    * Serialize mixed resource object with a dynamic type resolved from data
-   *
    * @see {@link http://jsonapi.org/format/#document-resource-objects}
    * @function JSONAPISerializer#serializeMixedResource
    * @private
@@ -592,7 +579,7 @@ module.exports = class JSONAPISerializer {
    * @param {object|object[]} data input data.
    * @param {Map<string, object>} [included] Included resources.
    * @param {object} [extraData] additional data.
-   * @param {object} [overrideSchemaOptions={}] additional schema options, a map of types with options to override.
+   * @param {object} [overrideSchemaOptions] additional schema options, a map of types with options to override.
    * @returns {object|object[]} serialized data.
    */
   serializeMixedResource(typeOption, data, included, extraData, overrideSchemaOptions = {}) {
@@ -603,7 +590,7 @@ module.exports = class JSONAPISerializer {
 
     if (Array.isArray(data)) {
       return data.map((d) =>
-        this.serializeMixedResource(typeOption, d, included, extraData, overrideSchemaOptions)
+        this.serializeMixedResource(typeOption, d, included, extraData, overrideSchemaOptions),
       );
     }
 
@@ -626,7 +613,6 @@ module.exports = class JSONAPISerializer {
 
   /**
    * Serialize 'attributes' key of resource objects: an attributes object representing some of the resource's data.
-   *
    * @see {@link http://jsonapi.org/format/#document-resource-object-attributes}
    * @function JSONAPISerializer#serializeAttributes
    * @private
@@ -665,7 +651,6 @@ module.exports = class JSONAPISerializer {
 
   /**
    * Serialize 'relationships' key of resource objects: a relationships object describing relationships between the resource and other JSON API resources.
-   *
    * @see {@link http://jsonapi.org/format/#document-resource-object-relationships}
    * @function JSONAPISerializer#serializeRelationships
    * @private
@@ -673,7 +658,7 @@ module.exports = class JSONAPISerializer {
    * @param {Options} options resource's configuration options.
    * @param {Map<string, object>} [included]  Included resources.
    * @param {object} [extraData] additional data.
-   * @param {object} [overrideSchemaOptions={}] additional schema options, a map of types with options to override.
+   * @param {object} [overrideSchemaOptions] additional schema options, a map of types with options to override.
    * @returns {object} serialized relationships.
    */
   serializeRelationships(data, options, included, extraData, overrideSchemaOptions = {}) {
@@ -698,7 +683,7 @@ module.exports = class JSONAPISerializer {
           included,
           data,
           extraData,
-          overrideSchemaOptions
+          overrideSchemaOptions,
         ),
       };
 
@@ -721,7 +706,6 @@ module.exports = class JSONAPISerializer {
 
   /**
    * Serialize 'data' key of relationship's resource objects.
-   *
    * @see {@link http://jsonapi.org/format/#document-resource-object-linkage}
    * @function JSONAPISerializer#serializeRelationship
    * @private
@@ -731,7 +715,7 @@ module.exports = class JSONAPISerializer {
    * @param {Map<string, object>} [included] Included resources.
    * @param {object} [data] the entire resource's data.
    * @param {object} [extraData] additional data.
-   * @param {object} [overrideSchemaOptions={}] additional schema options, a map of types with options to override.
+   * @param {object} [overrideSchemaOptions] additional schema options, a map of types with options to override.
    * @returns {object|object[]} serialized relationship data.
    */
   serializeRelationship(
@@ -741,7 +725,7 @@ module.exports = class JSONAPISerializer {
     included,
     data,
     extraData,
-    overrideSchemaOptions = {}
+    overrideSchemaOptions = {},
   ) {
     included = included || new Map();
     const schema = rSchema || 'default';
@@ -765,8 +749,8 @@ module.exports = class JSONAPISerializer {
           included,
           data,
           extraData,
-          overrideSchemaOptions
-        )
+          overrideSchemaOptions,
+        ),
       );
     }
 
@@ -804,7 +788,7 @@ module.exports = class JSONAPISerializer {
         rOptions,
         included,
         extraData,
-        overrideSchemaOptions
+        overrideSchemaOptions,
       );
 
       serializedRelationship.id = serializedIncluded.id;
@@ -837,7 +821,6 @@ module.exports = class JSONAPISerializer {
   /**
    * Process options values.
    * Allows options to be an object or a function with 1 or 2 arguments
-   *
    * @function JSONAPISerializer#processOptionsValues
    * @private
    * @param {object} data data passed to functions options.
@@ -876,7 +859,6 @@ module.exports = class JSONAPISerializer {
 
   /**
    * Get the schema options for the given type and optional schema.
-   *
    * @function JSONAPISerializer#_getSchemaOptions
    * @private
    * @param {string|object} [type] the type to get schema options for.
@@ -918,7 +900,6 @@ module.exports = class JSONAPISerializer {
 
   /**
    * Recursively convert object keys case
-   *
    * @function JSONAPISerializer#_convertCase
    * @private
    * @param {object|object[]|string} data to convert
@@ -949,7 +930,7 @@ module.exports = class JSONAPISerializer {
           result[this._convertCase(key, convertCaseOptions)] = converted;
           return result;
         },
-        {}
+        {},
       );
     }
 
@@ -998,7 +979,7 @@ module.exports = class JSONAPISerializer {
  * @property {Function|object} [topLevelLinks] describes the top-level links
  * @property {Function|object} [topLevelMeta] describes the top-level meta
  * @property {Function|object} [meta] describes resource-level meta
- * @property {object.<string, RelationshipOptions>} [relationships] an object defining some relationships
+ * @property {{[key: string]: RelationshipOptions}} [relationships] an object defining some relationships
  * @property {string[]} [blacklistOnDeserialize=[]] an array of blacklisted attributes. Default = []
  * @property {string[]} [whitelistOnDeserialize=[]] an array of whitelisted attributes. Default = []
  * @property {('kebab-case'|'snake_case'|'camelCase')} [convertCase] case conversion for serializing data
diff --git a/lib/helpers.js b/lib/helpers.js
index 0adb5c9..d2a4ea2 100644
--- a/lib/helpers.js
+++ b/lib/helpers.js
@@ -21,7 +21,7 @@ const set = (obj, path, value) => {
     (
       a,
       c,
-      i // Iterate all of them except the last one
+      i, // Iterate all of them except the last one
     ) =>
       Object(a[c]) === a[c] // Does the key exist and is its value an object?
         ? // Yes: then follow that path
@@ -32,7 +32,7 @@ const set = (obj, path, value) => {
             Math.abs(path[i + 1]) >> 0 === +path[i + 1]
               ? [] // Yes: assign a new array object
               : {}), // No: assign a new plain object
-    obj
+    obj,
   )[path[path.length - 1]] = value; // Finally assign the value to the last key
   return obj; // Return the top-level object to allow chaining
 };
diff --git a/lib/validator.js b/lib/validator.js
index 663a211..c5922e8 100644
--- a/lib/validator.js
+++ b/lib/validator.js
@@ -1,6 +1,5 @@
 /**
  * Validate and apply default values to resource's configuration options.
- *
  * @function validateOptions
  * @private
  * @param {object} options Configuration options.
@@ -57,7 +56,7 @@ function validateOptions(options) {
     !['kebab-case', 'snake_case', 'camelCase'].includes(options.unconvertCase)
   )
     throw new Error(
-      "option 'unconvertCase' must be one of 'kebab-case', 'snake_case', 'camelCase'"
+      "option 'unconvertCase' must be one of 'kebab-case', 'snake_case', 'camelCase'",
     );
 
   if (options.beforeSerialize && typeof options.beforeSerialize !== 'function')
@@ -109,7 +108,6 @@ function validateOptions(options) {
 
 /**
  * Validate and apply default values to the dynamic type object option.
- *
  * @function validateDynamicTypeOptions
  * @private
  * @param {object} options dynamic type object option.
@@ -145,7 +143,6 @@ function validateDynamicTypeOptions(options) {
 
 /**
  * Validate a JSON:API error object
- *
  * @function validateError
  * @private
  * @throws Will throw an error if the argument is not an object
@@ -164,9 +161,8 @@ function validateError(err) {
    * if present, contains valid members. From the JSON:API spec:
    *
    * links: a links object containing the following members:
-   *   about: a link that leads to further details about this particular
-   *          occurrence of the problem.
-   *
+   * about: a link that leads to further details about this particular
+   * occurrence of the problem.
    * @function isValidLink
    * @private
    * @see https://jsonapi.org/format/#error-objects
@@ -201,13 +197,12 @@ function validateError(err) {
    * if present, contains valid members. From the JSON:API spec:
    *
    * source: an object containing references to the source of the error,
-   *         optionally including any of the following members:
-   *   pointer: a JSON Pointer [RFC6901] to the associated entity in the
-   *            request document [e.g. "/data" for a primary data object,
-   *            or "/data/attributes/title" for a specific attribute].
-   *   parameter: a string indicating which URI query parameter caused the
-   *              error.
-   *
+   * optionally including any of the following members:
+   * pointer: a JSON Pointer [RFC6901] to the associated entity in the
+   * request document [e.g. "/data" for a primary data object,
+   * or "/data/attributes/title" for a specific attribute].
+   * parameter: a string indicating which URI query parameter caused the
+   * error.
    * @function isValidSource
    * @private
    * @see https://jsonapi.org/format/#error-objects
@@ -247,8 +242,7 @@ function validateError(err) {
    * the JSON:API spec:
    *
    * meta: a meta object containing non-standard meta-information about
-   *       the error.
-   *
+   * the error.
    * @function isValidMeta
    * @private
    * @see https://jsonapi.org/format/#error-objects
@@ -266,7 +260,6 @@ function validateError(err) {
 
   /**
    * Determines if the provided number is a valid HTTP status code.
-   *
    * @function isValidHttpStatusCode
    * @private
    * @see https://jsonapi.org/format/#error-objects
@@ -301,8 +294,7 @@ function validateError(err) {
    * HTTP status code. From the JSON:API spec:
    *
    * status: the HTTP status code applicable to this problem, expressed
-   *         as a string value.
-   *
+   * as a string value.
    * @function isValidStatus
    * @private
    * @see https://jsonapi.org/format/#error-objects
diff --git a/test/unit/validator.test.js b/test/unit/validator.test.js
index 60642f2..8818436 100644
--- a/test/unit/validator.test.js
+++ b/test/unit/validator.test.js
@@ -142,7 +142,7 @@ describe('validator', function () {
         });
       }).to.throw(
         Error,
-        "option 'convertCase' must be one of 'kebab-case', 'snake_case', 'camelCase'"
+        "option 'convertCase' must be one of 'kebab-case', 'snake_case', 'camelCase'",
       );
 
       done();
@@ -155,7 +155,7 @@ describe('validator', function () {
         });
       }).to.throw(
         Error,
-        "option 'unconvertCase' must be one of 'kebab-case', 'snake_case', 'camelCase'"
+        "option 'unconvertCase' must be one of 'kebab-case', 'snake_case', 'camelCase'",
       );
 
       done();