If the module is a single dts file, show it in the README

packages/definitions-parser/src/packages.ts

@@ -573,6 +573,9 @@ export class TypingsData extends PackageBase {
   get files(): readonly string[] {
     return this.data.files;
   }
+  get dtsFiles(): readonly string[] {
+    return this.data.files.filter(f => f.endsWith(".d.ts"));
+  }
   get license(): License {
     return this.data.license;
   }

packages/publisher/src/generate-packages.ts

@@ -98,13 +98,13 @@ async function generateTypingPackage(
   await writeCommonOutputs(
     typing,
     createPackageJSON(typing, version, packages, Registry.NPM),
-    createReadme(typing),
+    createReadme(typing, packageFS),
     Registry.NPM
   );
   await writeCommonOutputs(
     typing,
     createPackageJSON(typing, version, packages, Registry.Github),
-    createReadme(typing),
+    createReadme(typing, packageFS),
     Registry.Github
   );
   await Promise.all(
@@ -258,7 +258,7 @@ export function createNotNeededPackageJSON(
   return JSON.stringify(out, undefined, 4);
 }
 
-export function createReadme(typing: TypingsData): string {
+export function createReadme(typing: TypingsData, packageFS: FS): string {
   const lines: string[] = [];
   lines.push("# Installation");
   lines.push(`> \`npm install --save ${typing.fullNpmName}\``);
@@ -275,6 +275,15 @@ export function createReadme(typing: TypingsData): string {
   lines.push("# Details");
   lines.push(`Files were exported from ${definitelyTypedURL}/tree/${sourceBranch}/types/${typing.subDirectoryPath}.`);
 
+  if (typing.dtsFiles.length === 1 && packageFS.readFile(typing.dtsFiles[0]).length < 2500) {
+    const dts = typing.dtsFiles[0]
+    const url = `${definitelyTypedURL}/tree/${sourceBranch}/types/${typing.subDirectoryPath}/${dts}`
+    lines.push(`## [${typing.dtsFiles[0]}](${url})`)
+    lines.push("````ts")
+    lines.push(packageFS.readFile(dts))
+    lines.push("````")
+  }
+
   lines.push("");
   lines.push("### Additional Details");
   lines.push(` * Last updated: ${new Date().toUTCString()}`);

packages/publisher/test/generate-packages.test.ts

@@ -15,7 +15,7 @@ import {
   createMockDT
 } from "@definitelytyped/definitions-parser";
 import { testo } from "./utils";
-import { Registry } from "@definitelytyped/utils";
+import { Registry, InMemoryFS, Dir, FS } from "@definitelytyped/utils";
 
 function createRawPackage(license: License): TypingsDataRaw {
   return {
@@ -51,6 +51,19 @@ function createTypesData(): TypesDataFile {
 function createUnneededPackage() {
   return new NotNeededPackage("absalom", "alternate", "1.1.1");
 }
+
+function defaultFS(): FS {
+  const pkg = new Dir(undefined);
+  pkg.set(
+    "index.d.ts",
+    `type T = import("./types");
+`
+  );
+  pkg.set("jquery.test.ts", "// tests");
+  const memFS = new InMemoryFS(pkg, "types/mock");
+  return memFS
+}
+
 testo({
   mitLicenseText() {
     const typing = new TypingsData(createRawPackage(License.MIT), /*isLatest*/ true);
@@ -62,21 +75,32 @@ testo({
   },
   basicReadme() {
     const typing = new TypingsData(createRawPackage(License.Apache20), /*isLatest*/ true);
-    expect(createReadme(typing)).toEqual(expect.stringContaining("This package contains type definitions for"));
+    expect(createReadme(typing, defaultFS())).toEqual(expect.stringContaining("This package contains type definitions for"));
   },
   readmeContainsProjectName() {
     const typing = new TypingsData(createRawPackage(License.Apache20), /*isLatest*/ true);
-    expect(createReadme(typing)).toEqual(expect.stringContaining("jquery.org"));
+    expect(createReadme(typing, defaultFS())).toEqual(expect.stringContaining("jquery.org"));
   },
   readmeOneDependency() {
     const typing = new TypingsData(createRawPackage(License.Apache20), /*isLatest*/ true);
-    expect(createReadme(typing)).toEqual(
+    expect(createReadme(typing, defaultFS())).toEqual(
       expect.stringContaining("Dependencies: [@types/madeira](https://npmjs.com/package/@types/madeira)")
     );
   },
+  readmeContainsSingleFileDTS() {
+    const typing = new TypingsData(createRawPackage(License.Apache20), /*isLatest*/ true);
+    expect(createReadme(typing, defaultFS())).toContain("type T = import")
+  },
+  readmeContainsManyDTSFilesDoesNotAmendREADME() {
+    const rawPkg = createRawPackage(License.Apache20)
+    // @ts-expect-error - files is readonly
+    rawPkg.files = ["index.d.ts", "other.d.ts"]
+    const typing = new TypingsData(rawPkg, /*isLatest*/ true);
+    expect(createReadme(typing, defaultFS())).not.toContain("type T = import")
+  },
   readmeNoGlobals() {
     const typing = new TypingsData(createRawPackage(License.Apache20), /*isLatest*/ true);
-    expect(createReadme(typing)).toEqual(expect.stringContaining("Global values: none"));
+    expect(createReadme(typing, defaultFS())).toEqual(expect.stringContaining("Global values: none"));
   },
   basicPackageJson() {
     const packages = AllPackages.from(createTypesData(), readNotNeededPackages(createMockDT().fs));