fix(v2): fix bad @docusaurus/types Plugin type generics (#5058)

* fix(types): type `LoadedPlugin` is not generic

`LoadedPlugin` referenced line 201 is not generic, causing typescript errors on
end-user builds.

* chore(types): add typescript dev dep, tsconfig and a test script

Contributors will no longer inadvertently dump type errors since any IDE should
check types now.

* add missing plugins generic types

Co-authored-by: slorber <lorber.sebastien@gmail.com>

packages/docusaurus-types/package.json

@@ -13,11 +13,17 @@
     "directory": "packages/docusaurus-types"
   },
   "license": "MIT",
+  "scripts": {
+    "test": "tsc -p ."
+  },
   "dependencies": {
     "commander": "^5.1.0",
     "joi": "^17.4.0",
     "querystring": "0.2.0",
     "webpack": "^5.40.0",
     "webpack-merge": "^5.8.0"
+  },
+  "devDependencies": {
+    "typescript": "^4.3.4"
   }
 }

packages/docusaurus-types/src/index.d.ts

@@ -198,7 +198,7 @@ export interface Props extends LoadContext, InjectedHtmlTags {
   siteMetadata: DocusaurusSiteMetadata;
   routes: RouteConfig[];
   routesPaths: string[];
-  plugins: LoadedPlugin<unknown>[];
+  plugins: LoadedPlugin[];
 }
 
 export interface PluginContentLoadedActions {
@@ -219,7 +219,7 @@ export type AllContent = Record<
 // TODO improve type (not exposed by postcss-loader)
 export type PostCssOptions = Record<string, unknown> & {plugins: unknown[]};
 
-export interface Plugin<Content> {
+export interface Plugin<Content = unknown> {
   name: string;
   loadContent?(): Promise<Content>;
   contentLoaded?({
@@ -283,12 +283,14 @@ export interface Plugin<Content> {
   }): ThemeConfig;
 }
 
-export type InitializedPlugin = Plugin<unknown> & {
+export type InitializedPlugin<Content = unknown> = Plugin<Content> & {
   readonly options: PluginOptions;
   readonly version: DocusaurusPluginVersionInformation;
 };
 
-export type LoadedPlugin = InitializedPlugin & {readonly content: unknown};
+export type LoadedPlugin<Content = unknown> = InitializedPlugin<Content> & {
+  readonly content: Content;
+};
 
 export type PluginModule = {
   <T, X>(context: LoadContext, options: T): Plugin<X>;

packages/docusaurus-types/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "$schema": "http://json.schemastore.org/tsconfig",
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "noEmit": true
+  }
+}

yarn.lock

@@ -18490,6 +18490,11 @@ typescript@^4.1.5:
   resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.3.2.tgz#399ab18aac45802d6f2498de5054fcbbe716a805"
   integrity sha512-zZ4hShnmnoVnAHpVHWpTcxdv7dWP60S2FsydQLV8V5PbS3FifjWFFRiHSWpDJahly88PRyV5teTSLoq4eG7mKw==
 
+typescript@^4.3.4:
+  version "4.3.4"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.3.4.tgz#3f85b986945bcf31071decdd96cf8bfa65f9dcbc"
+  integrity sha512-uauPG7XZn9F/mo+7MrsRjyvbxFpzemRjKEZXS4AK83oP2KKOJPvb+9cO/gmnv8arWZvhnjVOXz7B49m1l0e9Ew==
+
 ua-parser-js@^0.7.18:
   version "0.7.28"
   resolved "https://registry.yarnpkg.com/ua-parser-js/-/ua-parser-js-0.7.28.tgz#8ba04e653f35ce210239c64661685bf9121dec31"