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PDF files

You can use this version of the popular PDFLoader in web environments. By default, one document will be created for each page in the PDF file, you can change this behavior by setting the splitPages option to false.

Setup​

npm install pdf-parse

Usage​

import { WebPDFLoader } from "langchain/document_loaders/web/pdf";

const blob = new Blob(); // e.g. from a file input

const loader = new WebPDFLoader(blob);

const docs = await loader.load();

console.log({ docs });

API Reference:

Usage, custom pdfjs build​

By default we use the pdfjs build bundled with pdf-parse, which is compatible with most environments, including Node.js and modern browsers. If you want to use a more recent version of pdfjs-dist or if you want to use a custom build of pdfjs-dist, you can do so by providing a custom pdfjs function that returns a promise that resolves to the PDFJS object.

In the following example we use the "legacy" (see pdfjs docs) build of pdfjs-dist, which includes several polyfills not included in the default build.

npm install pdfjs-dist
import { WebPDFLoader } from "langchain/document_loaders/web/pdf";

const blob = new Blob(); // e.g. from a file input

const loader = new WebPDFLoader(blob, {
  // you may need to add `.then(m => m.default)` to the end of the import
  pdfjs: () => import("pdfjs-dist/legacy/build/pdf.js"),
});

Eliminating extra spaces​

PDFs come in many varieties, which makes reading them a challenge. The loader parses individual text elements and joins them together with a space by default, but if you are seeing excessive spaces, this may not be the desired behavior. In that case, you can override the separator with an empty string like this:

import { WebPDFLoader } from "langchain/document_loaders/web/pdf";

const blob = new Blob(); // e.g. from a file input

const loader = new WebPDFLoader(blob, {
  parsedItemSeparator: "",
});

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