Feature/mi 255 fix types for optional request body

package.json

@@ -50,21 +50,22 @@
     "@aligent/ts-code-standards": "^4.0.2",
     "@types/node": "^22.16.5",
     "diff": "^8.0.2",
-    "eslint": "^9.31.0",
-    "openapi-typescript": "^7.8.0",
+    "eslint": "^9.34.0",
+    "openapi-typescript": "^7.9.1",
     "prettier": "^3.6.2",
     "rimraf": "^6.0.1",
     "simple-git": "^3.28.0",
     "ts-morph": "^26.0.0",
-    "tsd": "^0.32.0",
+    "tsd": "^0.33.0",
     "tshy": "^3.0.2",
-    "typescript": "^5.8.3",
+    "typescript": "^5.9.2",
+    "typescript-eslint": "^8.41.0",
     "uuid": "^11.1.0"
   },
   "dependencies": {
     "form-data": "^4.0.4",
     "node-fetch": "^3.3.2",
     "query-string": "^9.2.2"
   },
-  "packageManager": "[email protected].2"
+  "packageManager": "[email protected].4"
 }

src/internal/operation.ts

@@ -8,10 +8,14 @@ import { Agent as HttpsAgent } from 'https';
 import fetch, { Response as FetchResponse } from 'node-fetch';
 import qs from 'query-string';
 
-// Represents HTTP methods supported by the API
+/**
+ * @description HTTP methods supported by the API
+ */
 export type RequestMethod = 'DELETE' | 'GET' | 'PATCH' | 'POST' | 'PUT';
 
-// Represents a complete API request with its endpoint and parameters
+/**
+ * @description Represents a complete API request with its endpoint and parameters
+ */
 export type Request<
     ReqLine extends RequestLine = RequestLine,
     Params extends Parameters = Parameters,
@@ -20,23 +24,37 @@ export type Request<
     readonly parameters: Params;
 };
 
-// Represents an API endpoint in the format "METHOD /path"
-// e.g., "GET /products" or "POST /orders"
+/**
+ * @description Represents an API endpoint in the format "METHOD /path"
+ * e.g., "GET /products" or "POST /orders"
+ */
 export type RequestLine = `${RequestMethod} ${string}`;
 
-// Represents all possible parameter types that can be sent with a request:
-// - path: URL path parameters (e.g., /products/{id})
-// - query: URL query parameters
-// - body: Request body data
-// - header: Custom HTTP headers
+/**
+ * @description Represents all possible parameter types that can be sent with a request:
+ */
 export type Parameters = {
+    /**
+     * @description URL path parameters (e.g., /products/{id})
+     */
     readonly path?: Record<string, any>;
+    /**
+     * @description URL query parameters
+     */
     readonly query?: any;
+    /**
+     * @description Request body data
+     */
     readonly body?: any;
+    /**
+     * @description Custom HTTP headers
+     */
     readonly header?: Record<string, any>;
 };
 
-// Represents an API response with status code and optional body
+/**
+ * @description Represents an API response with status code and optional body
+ */
 export type Response = {
     readonly status: number | string;
     readonly body?: any;
@@ -45,14 +63,20 @@ export type Response = {
 // Namespace for response-related type utilities
 export namespace Response {
     type SuccessStatus = 200 | 201 | 204;
+
+    /**
+     * @description Extracts and formats the possible success responses for an operation
+     */
     export type Success<T extends Response | Operation> = T extends Operation
         ? Success<T['response']>
         : T extends { status: SuccessStatus }
           ? T
           : never;
 }
 
-// Represents a complete API operation with its parameters and expected response
+/**
+ * @description Represents a complete API operation with its parameters and expected response
+ */
 export type Operation = {
     readonly parameters: Request['parameters'];
     readonly response: Response;
@@ -61,43 +85,59 @@ export type Operation = {
 // Namespace for operation-related type utilities
 // TODO: MI-199 - determine if this is still required
 export namespace Operation {
-    // Extracts the minimal required input parameters for an operation
+    /**
+     * @description Extracts the minimal required input parameters for an operation
+     */
     export type MinimalInput<Op extends Operation> = InputParameters<Op['parameters']>;
 
-    // Transforms API parameters based on their type:
-    // - query parameters are made optional (Partial)
-    // - header parameters have Accept and Content-Type removed since they're handled by the client
-    // - all other parameters (path, body) are kept as-is
-    // TODO: MI-199 should we be making params partial?
-    type TransformParam<
+    /**
+     * @description Makes properties optional if they're on the 'query' object
+     */
+    type MakeQueryParamsOptional<
         OpParams extends Operation['parameters'],
         K extends keyof OpParams,
     > = K extends 'query' ? Partial<OpParams[K]> : OpParams[K];
 
-    // Transforms operation parameters to make certain fields optional
+    /**
+     * @description Makes properties optional if they can be empty objects
+     */
+    type MakeEmptyObjectOptional<T> = {
+        readonly [K in keyof T as {} extends T[K] ? K : never]?: T[K];
+    } & {
+        readonly [K in keyof T as {} extends T[K] ? never : K]: T[K];
+    };
+
+    /**
+     * @description Prepares request parameters by making query params and any possibly empty params optional
+     */
     type InputParameters<OpParams extends Operation['parameters']> = MakeEmptyObjectOptional<{
-        [K in keyof OpParams]: TransformParam<OpParams, K>;
+        [K in keyof OpParams]: MakeQueryParamsOptional<OpParams, K>;
     }>;
 }
 
-// Maps request lines to their corresponding operations
+/**
+ * @description Maps request lines to their corresponding operations
+ */
 export type OperationIndex = Record<string, Operation>;
 
 // Namespace for operation index utilities
 export namespace OperationIndex {
-    // Filters operations to only include those with optional parameters
+    /**
+     * @description Filters operations to only include those with optional parameters
+     */
     export type FilterOptionalParams<Ops extends OperationIndex> = {
         [K in keyof Ops as {} extends Ops[K]['parameters'] ? K : never]: Ops[K];
     };
 }
 
-// Utility type that makes properties optional if they can be empty objects
-type MakeEmptyObjectOptional<T> = {
-    readonly [K in keyof T as {} extends T[K] ? K : never]?: T[K];
-} & {
-    readonly [K in keyof T as {} extends T[K] ? never : K]: T[K];
-};
-
+/**
+ * @description Resolves the path for a request
+ * @example
+ * ```ts
+ * resolvePath('/products/{id}', { id: 123 })
+ * // returns '/products/123'
+ * ```
+ */
 export function resolvePath(parameterizedPath: string, pathParams: Record<string, any>): string {
     return parameterizedPath
         .split('/')
@@ -116,10 +156,14 @@ export function resolvePath(parameterizedPath: string, pathParams: Record<string
         .join('/');
 }
 
-// Transport function type that handles making the actual API requests
+/**
+ * @description Transport function type that handles making the actual API requests
+ */
 export type Transport = (requestLine: string, params?: Parameters) => Promise<Response>;
 
-// Configuration options for the fetch-based transport
+/**
+ * @description Configuration options for the fetch-based transport
+ */
 export type FetchTransportOptions = {
     readonly baseUrl: string;
     readonly headers: Record<string, string>;
@@ -165,6 +209,20 @@ const defaultRetryConfig: Exclude<FetchTransportOptions['retry'], boolean | unde
     },
 };
 
+/**
+ * @description Creates a fetch transport function
+ * @example
+ * ```ts
+ * const transport = fetchTransport({
+ *     baseUrl: 'https://api.bigcommerce.com/stores/1234567890/v3',
+ *     headers: {
+ *         'X-Auth-Token': '1234567890',
+ *     },
+ * });
+ * ```
+ * @param options - The options for the fetch transport
+ * @returns
+ */
 export function fetchTransport(options: FetchTransportOptions): Transport {
     const { agent, baseUrl, headers, retry } = options;
 

src/internal/reference/operation-inference.ts

@@ -1,53 +1,110 @@
-// TECH DEBT: Work out if these eslint rules are reasonable in this context
-/* eslint-disable @typescript-eslint/no-empty-object-type */
-/* eslint-disable @typescript-eslint/no-explicit-any */
 import type { RequestMethod } from '../operation.js';
+import type { Flatten, IsOptional } from '../type-utils.js';
 
 // Takes an OpenAPI paths specification and converts it into our internal operation index format,
 // removing any undefined endpoints and flattening the paths into a single type
+/**
+ * @description Converts an OpenAPI paths specification into our internal operation index format
+ * - REST operations are combined with their parent path e.g. 'GET /path/a'
+ * - Parameters are kept, or defaulted to an empty object if not present
+ * - Response and Request objects are reformatted with generics
+ *
+ * Only application/json request and response bodies are included
+ *
+ * @example
+ * ```ts
+ * type A = InferOperationIndex<{
+ *   '/path/a': {
+ *      put: {
+ *          parameters: { a: string };
+ *          requestBody: { content: { 'application/json': { b: string } } };
+ *      };
+ *   };
+ * }>;
+ * // A is {
+ * //   'PUT /path/a': RequiredRequestBody<{
+ * //          a: string;
+ * //       },
+ * //       unknown,
+ * //       {
+ * //          b: string;
+ * //       }>
+ * //   }
+ */
 export type InferOperationIndex<PathsSpec> = Flatten<{
     [PathStr in keyof PathsSpec & string]: PathOperationIndex<PathStr, PathsSpec[PathStr]>;
 }>;
 
-// Takes a record of types and flattens them into a single intersection type
-// This combines all the operations from different paths into one type
-type Flatten<T extends Record<string, any>> = UnionToIntersection<T[keyof T]>;
-type UnionToIntersection<T> = (T extends any ? (x: T) => any : never) extends (x: infer R) => any
-    ? R
-    : never;
-
-// Converts an OpenAPI 3.0 path specification into our operation index format
-// Currently this only extracts type details for application/json request bodies
+/**
+ * @description Formats the OpenAPI parameters, responses, and responseBody specs at a given path
+ * in preparation for flattening the paths in to a single index type
+ *
+ * @see InferOperationIndex for more information
+ */
 type PathOperationIndex<Path extends string, PathSpec> = {
-    [K in keyof PathSpec as K extends RequestMethodLc
-        ? `${Uppercase<K>} ${Path}`
-        : never]: PathSpec[K] extends { parameters?: infer Params; responses?: infer Responses }
-        ? PathSpec[K] extends {
-              requestBody: { content: { 'application/json': infer RequestBody } };
+    [K in keyof PathSpec as PathKey<K, Path>]: PathSpec[K] extends {
+        parameters?: infer Params;
+        responses?: infer Responses;
+    }
+        ? {
+              parameters: Params & ParamsRequestBody<PathSpec[K]>;
+              response: ResponseUnion<Responses>;
           }
-            ? {
-                  readonly parameters: (unknown extends Params ? {} : Params) & {
-                      body: RequestBody;
-                  };
-                  readonly response: Response<Responses>;
-              }
-            : {
-                  readonly parameters: unknown extends Params ? {} : Params;
-                  readonly response: Response<Responses>;
-              }
         : never;
 };
 
-// Lowercase version of our RequestMethod type
-// Used for matching HTTP methods in OpenAPI specs which are typically lowercase
-type RequestMethodLc = Lowercase<RequestMethod>;
+/**
+ * @description Combines the REST operation method with the endpoint path to form a unique key
+ * @example
+ * ```ts
+ * type A = PathKey<'get', '/path/a'>
+ * // A is 'GET /path/a'
+ */
+type PathKey<K, Path extends string> =
+    K extends Lowercase<RequestMethod> ? `${Uppercase<K>} ${Path}` : never;
 
-// Converts OpenAPI response specifications into our internal response format
-type Response<ResponsesSpec> = {
+/**
+ * @description Converts OpenAPI response specifications into a union of possible responses
+ * Only responses with a 'application/json' content type are included
+ *
+ * @example
+ * ```ts
+ * type A = Response<{
+ *   200: { content: { 'application/json': { a: string } } };
+ *   204: { content: { 'application/json': {} } };
+ * }>;
+ * // A is { status: 200, body: { a: string } } | { status: 204, body: {} }
+ * ```
+ */
+type ResponseUnion<ResponsesSpec> = {
     [Status in keyof ResponsesSpec]: {
         status: Status;
         body: ResponsesSpec[Status] extends { content: { 'application/json': infer ResponseBody } }
             ? ResponseBody
             : never;
     };
 }[keyof ResponsesSpec];
+
+/**
+ * @description Extracts the request body from an OpenAPI specification
+ * - Keeps the optional or required nature of the request body from the original spec
+ * - Only includes 'application/json' content type request bodies
+ * - Returns a type with no body property if the original spec has no request body property (e.g. GET requests)
+ *
+ * @example
+ * ```ts
+ * type A = ParamsRequestBody<{
+ *   requestBody: { content: { 'application/json': { a: string } } };
+ * }>;
+ * // A is { body: { a: string } }
+ * ```
+ */
+type ParamsRequestBody<PathSpec> = PathSpec extends {
+    requestBody?: { content: { 'application/json': infer RequestBody } };
+}
+    ? unknown extends RequestBody
+        ? unknown
+        : IsOptional<PathSpec, 'requestBody'> extends true
+          ? Partial<{ body: RequestBody }>
+          : { body: RequestBody }
+    : never;