pdf-to-img/dist/index.js

📃📸 Converts PDFs to images in nodejs

import { createRequire } from "node:module";
import path from "node:path/posix";
import * as pdfjs from "pdfjs-dist/legacy/build/pdf.mjs";
import { parseInput } from "./parseInput.js";
const pdfjsPath = path.dirname(createRequire(import.meta.url).resolve("pdfjs-dist/package.json"));
/** required since k-yle/pdf-to-img#58, the objects from pdfjs are weirdly structured */
const sanitize = (x) => {
    // eslint-disable-next-line unicorn/prefer-structured-clone -- TODO: wait for min nodejs version to be bumped
    const object = JSON.parse(JSON.stringify(x));
    // remove UTF16 BOM and weird 0x0 character introduced in k-yle/pdf-to-img#138 and k-yle/pdf-to-img#184
    for (const key in object) {
        if (typeof object[key] === "string") {
            // eslint-disable-next-line no-control-regex -- this is deliberate
            object[key] = object[key].replaceAll(/(^þÿ|\u0000)/g, "");
        }
    }
    return object;
};
/**
 * Converts a PDF to a series of images. This returns a `Symbol.asyncIterator`
 *
 * @param input Either (a) the path to a pdf file, or (b) a data url, or (b) a buffer, (c) a buffer, or (e) a ReadableStream.
 *
 * @example
 * ```js
 * import pdf from "pdf-to-img";
 *
 * for await (const page of await pdf("example.pdf")) {
 *   expect(page).toMatchImageSnapshot();
 * }
 *
 * // or if you want access to more details:
 *
 * const doc = await pdf("example.pdf");
 * expect(doc.length).toBe(1);
 * expect(doc.metadata).toEqual({ ... });
 *
 * for await (const page of doc) {
 *   expect(page).toMatchImageSnapshot();
 * }
 * ```
 */
export async function pdf(input, options = {}) {
    const data = await parseInput(input);
    const pdfDocument = await pdfjs.getDocument({
        password: options.password,
        standardFontDataUrl: path.join(pdfjsPath, `standard_fonts${path.sep}`),
        cMapUrl: path.join(pdfjsPath, `cmaps${path.sep}`),
        cMapPacked: true,
        ...options.docInitParams,
        isEvalSupported: false,
        data,
    }).promise;
    const metadata = await pdfDocument.getMetadata();
    async function getPage(pageNumber) {
        const page = await pdfDocument.getPage(pageNumber);
        const viewport = page.getViewport({ scale: options.scale ?? 1 });
        const { canvas } = pdfDocument.canvasFactory.create(viewport.width, viewport.height, !!options.renderParams?.background);
        await page.render({
            canvas,
            viewport,
            ...options.renderParams,
        }).promise;
        return canvas.toBuffer("image/png");
    }
    return {
        length: pdfDocument.numPages,
        metadata: sanitize(metadata.info),
        getPage,
        [Symbol.asyncIterator]() {
            return {
                pg: 0,
                async next() {
                    if (this.pg < pdfDocument.numPages) {
                        this.pg += 1;
                        return { done: false, value: await getPage(this.pg) };
                    }
                    return { done: true, value: undefined };
                },
            };
        },
    };
}