Added a new method to read a specific page number

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## 4.1.0 (2024-08-07)
+
+- Added a new method to read a specific page number
+
 ## 4.0.0 (2024-06-08)
 
 - 💥 BREAKING CHANGE: Drop support for node v16. The minimum version is now v18

README.md

@@ -38,6 +38,10 @@ async function main() {
     await fs.writeFile(`page${counter}.png`, image);
     counter++;
   }
+
+
+  // you can also read a specific page number:
+  const page12buffer = await document.getPage(12)
 }
 main();
 ```

package.json

@@ -1,54 +1,54 @@
-{
-  "name": "pdf-to-img",
-  "version": "4.0.0",
-  "author": "Kyle Hensel",
-  "description": "📃📸 Converts PDFs to images in nodejs",
-  "exports": "./dist/index.js",
-  "types": "dist/index.d.ts",
-  "type": "module",
-  "license": "MIT",
-  "files": [
-    "dist"
-  ],
-  "keywords": [
-    "pdf",
-    "pdfjs",
-    "pdf-to-img",
-    "pdf-to-png",
-    "vitest",
-    "jest"
-  ],
-  "repository": "https://github.com/k-yle/pdf-to-img",
-  "scripts": {
-    "build": "tsc && rm -rf dist && mv temp/src dist && rm -rf temp",
-    "lint": "eslint --ignore-path .gitignore .",
-    "test": "vitest --pool=forks",
-    "trypublish": "npm publish --provenance || true"
-  },
-  "bin": {
-    "pdf2img": "./bin/cli.mjs"
-  },
-  "engines": {
-    "node": ">=18"
-  },
-  "engineStrict": true,
-  "dependencies": {
-    "canvas": "2.11.2",
-    "pdfjs-dist": "4.2.67"
-  },
-  "devDependencies": {
-    "@rushstack/eslint-patch": "^1.5.1",
-    "@types/jest-image-snapshot": "^6.2.1",
-    "@types/node": "^20.8.6",
-    "@types/pdfjs-dist": "2.10.377",
-    "@vitest/coverage-v8": "^1.6.0",
-    "eslint": "^8.50.0",
-    "eslint-config-kyle": "^14.12.3",
-    "jest-image-snapshot": "^6.2.0",
-    "typescript": "^5.2.2",
-    "vitest": "^1.6.0"
-  },
-  "prettier": {
-    "trailingComma": "es5"
-  }
-}
+{
+  "name": "pdf-to-img",
+  "version": "4.1.0",
+  "author": "Kyle Hensel",
+  "description": "📃📸 Converts PDFs to images in nodejs",
+  "exports": "./dist/index.js",
+  "types": "dist/index.d.ts",
+  "type": "module",
+  "license": "MIT",
+  "files": [
+    "dist"
+  ],
+  "keywords": [
+    "pdf",
+    "pdfjs",
+    "pdf-to-img",
+    "pdf-to-png",
+    "vitest",
+    "jest"
+  ],
+  "repository": "https://github.com/k-yle/pdf-to-img",
+  "scripts": {
+    "build": "tsc && rm -rf dist && mv temp/src dist && rm -rf temp",
+    "lint": "eslint --ignore-path .gitignore .",
+    "test": "vitest --pool=forks",
+    "trypublish": "npm publish --provenance || true"
+  },
+  "bin": {
+    "pdf2img": "./bin/cli.mjs"
+  },
+  "engines": {
+    "node": ">=18"
+  },
+  "engineStrict": true,
+  "dependencies": {
+    "canvas": "2.11.2",
+    "pdfjs-dist": "4.2.67"
+  },
+  "devDependencies": {
+    "@rushstack/eslint-patch": "^1.5.1",
+    "@types/jest-image-snapshot": "^6.2.1",
+    "@types/node": "^20.8.6",
+    "@types/pdfjs-dist": "2.10.377",
+    "@vitest/coverage-v8": "^1.6.0",
+    "eslint": "^8.50.0",
+    "eslint-config-kyle": "^14.12.3",
+    "jest-image-snapshot": "^6.2.0",
+    "typescript": "^5.2.2",
+    "vitest": "^1.6.0"
+  },
+  "prettier": {
+    "trailingComma": "es5"
+  }
+}

src/index.ts

@@ -73,6 +73,7 @@ export async function pdf(
 ): Promise<{
   length: number;
   metadata: PdfMetadata;
+  getPage(pageNumber: number): Promise<Buffer>;
   [Symbol.asyncIterator](): AsyncIterator<Buffer, void, void>;
 }> {
   const data = await parseInput(input);
@@ -91,30 +92,36 @@ export async function pdf(
 
   const metadata = await pdfDocument.getMetadata();
 
+  async function getPage(pageNumber: number) {
+    const page = await pdfDocument.getPage(pageNumber);
+
+    const viewport = page.getViewport({ scale: options.scale ?? 1 });
+
+    const { canvas, context } = canvasFactory.create(
+      viewport.width,
+      viewport.height
+    );
+
+    await page.render({
+      canvasContext: context,
+      viewport,
+    }).promise;
+
+    return canvas.toBuffer();
+  }
+
   return {
     length: pdfDocument.numPages,
     metadata: sanitize(metadata.info),
+    getPage,
     [Symbol.asyncIterator]() {
       return {
         pg: 0,
         async next(this: { pg: number }) {
           if (this.pg < pdfDocument.numPages) {
             this.pg += 1;
-            const page = await pdfDocument.getPage(this.pg);
-
-            const viewport = page.getViewport({ scale: options.scale ?? 1 });
-
-            const { canvas, context } = canvasFactory.create(
-              viewport.width,
-              viewport.height
-            );
-
-            await page.render({
-              canvasContext: context,
-              viewport,
-            }).promise;
 
-            return { done: false, value: canvas.toBuffer() };
+            return { done: false, value: await getPage(this.pg) };
           }
           return { done: true, value: undefined };
         },

tests/jsdom.test.ts

@@ -35,6 +35,11 @@ describe("multipage.pdf", () => {
       expect(page).toMatchImageSnapshot();
     }
   });
+
+  it("can read a specific page number", async () => {
+    const document = await pdf("./tests/multipage.pdf");
+    expect(await document.getPage(2)).toMatchImageSnapshot();
+  });
 });
 
 describe("test-pattern.pdf", () => {