Avoid adding undefined to the index signature for additionalProperties (#1295)

Co-authored-by: Piet van Agtmaal <piet@wonki.ai>

Author: pvanagtmaal

.changeset/ninety-tips-sip.md

@@ -0,0 +1,5 @@
+---
+"openapi-typescript": minor
+---
+
+Avoid adding a undefined union to additionProperties

docs/src/content/docs/advanced.md

@@ -182,6 +182,10 @@ However, APIs are language-agnostic, and may contain a different syntax style fr
 
 Instead, treat “consistency” in a more holistic sense, recognizing that preserving the API schema as-written is better than adhering to language-specific style conventions.
 
+### Enable `noUncheckedIndexAccess` in your tsconfig.json
+
+openapi-typescript generates a `Record` for `additionalProperties` and tries to avoid adding a `undefined` union to the index signature. However, this may result in unsafe property access in TypeScript, **unless** the compiler flag `noUncheckedIndexAccess` is set. If set, TypeScript will error when you try to access a property that might not be set.
+
 ### Be specific in your schema
 
 openapi-typescript will **never produce an `any` type**. Anything not explicated in your schema may as well not exist. For that reason, always be as specific as possible. Here’s how to get the most out of `additionalProperties`:

packages/openapi-typescript/examples/digital-ocean-api.ts

@@ -11958,7 +11958,7 @@ export interface external {
      * }
      */
     metric: {
-      [key: string]: string | undefined;
+      [key: string]: string;
     };
     /**
      * @example [

packages/openapi-typescript/examples/github-api-next.ts

@@ -12220,7 +12220,7 @@ export interface components {
           language?: string;
           raw_url?: string;
           size?: number;
-        } | undefined;
+        };
       };
       public: boolean;
       /** Format: date-time */
@@ -12360,7 +12360,7 @@ export interface components {
             language?: string;
             raw_url?: string;
             size?: number;
-          } | undefined;
+          };
         };
         public: boolean;
         /** Format: date-time */
@@ -12386,15 +12386,15 @@ export interface components {
       git_push_url?: string;
       html_url?: string;
       files?: {
-        [key: string]: ({
+        [key: string]: {
           filename?: string;
           type?: string;
           language?: string;
           raw_url?: string;
           size?: number;
           truncated?: boolean;
           content?: string;
-        } | null) | undefined;
+        } | null;
       };
       public?: boolean;
       created_at?: string;
@@ -13807,13 +13807,13 @@ export interface components {
       /** @description Permissions requested, categorized by type of permission. */
       permissions: {
         organization?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
         repository?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
         other?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
       };
       /** @description Date and time when the request for access was created. */
@@ -13843,13 +13843,13 @@ export interface components {
       /** @description Permissions requested, categorized by type of permission. */
       permissions: {
         organization?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
         repository?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
         other?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
       };
       /** @description Date and time when the fine-grained personal access token was approved to access the organization. */
@@ -17048,7 +17048,7 @@ export interface components {
      * @description User-defined metadata to store domain-specific information limited to 8 keys with scalar values.
      */
     metadata: {
-      [key: string]: (null | string | number | boolean) | undefined;
+      [key: string]: null | string | number | boolean;
     };
     dependency: {
       /** @description Package-url (PURL) of dependency. See https://github.com/package-url/purl-spec for more details. */
@@ -17077,7 +17077,7 @@ export interface components {
       metadata?: components["schemas"]["metadata"];
       /** @description A collection of resolved package dependencies. */
       resolved?: {
-        [key: string]: components["schemas"]["dependency"] | undefined;
+        [key: string]: components["schemas"]["dependency"];
       };
     };
     /**
@@ -17111,7 +17111,7 @@ export interface components {
       metadata?: components["schemas"]["metadata"];
       /** @description A collection of package manifests, which are a collection of related dependencies declared in a file or representing a logical group of dependencies. */
       manifests?: {
-        [key: string]: components["schemas"]["manifest"] | undefined;
+        [key: string]: components["schemas"]["manifest"];
       };
       /**
        * Format: date-time
@@ -18250,7 +18250,7 @@ export interface components {
      * @description Language
      */
     language: {
-      [key: string]: number | undefined;
+      [key: string]: number;
     };
     /**
      * License Content
@@ -20594,37 +20594,37 @@ export interface components {
       /** @description New requested permissions, categorized by type of permission. */
       permissions_added: {
         organization?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
         repository?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
         other?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
       };
       /** @description Requested permissions that elevate access for a previously approved request for access, categorized by type of permission. */
       permissions_upgraded: {
         organization?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
         repository?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
         other?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
       };
       /** @description Permissions requested, categorized by type of permission. This field incorporates `permissions_added` and `permissions_upgraded`. */
       permissions_result: {
         organization?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
         repository?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
         other?: {
-          [key: string]: string | undefined;
+          [key: string]: string;
         };
       };
       /**
@@ -37960,12 +37960,12 @@ export interface components {
       };
       platform?: string;
       metadata?: {
-        [key: string]: string | undefined;
+        [key: string]: string;
       };
       repo?: string;
-      dependencies?: ({
-          [key: string]: string | undefined;
-        })[];
+      dependencies?: {
+          [key: string]: string;
+        }[];
       commit_oid?: string;
     };
     /** package published event */
@@ -78906,7 +78906,7 @@ export interface operations {
       200: {
         content: {
           "application/json": {
-            [key: string]: string | undefined;
+            [key: string]: string;
           };
         };
       };
@@ -79078,7 +79078,7 @@ export interface operations {
             [key: string]: {
               /** @description Content of the file */
               content: string;
-            } | undefined;
+            };
           };
           public?: boolean | ("true" | "false");
         };
@@ -79215,12 +79215,12 @@ export interface operations {
            * To delete a file, set the whole file to null. For example: `hello.py : null`.
            */
           files?: {
-            [key: string]: (({
+            [key: string]: ({
               /** @description The new content of the file. */
               content?: string;
               /** @description The new filename for the file. */
               filename?: string | null;
-            }) | null) | undefined;
+            }) | null;
           };
         }) | null;
       };