---
title: "Configure the Advanced I/O function"
url: https://docs.catalyst.zoho.com/en/tutorials/document-processor/nodejs/configure-advancedio/
description: "Create a React web app that detects and extracts data from input documents, and processes it using  OCR, Barcode Scanner, and Identity Scanner of Zia Services."
last_updated: 2026-08-17T12:16:04Z
service: All Services
type: tutorial
related_links:
  - name: "Functions Directory Structure"
    url: /en/cli/v1/project-directory-structure/functions-directory
  - name: "Advanced I/O Function"
    url: /en/serverless/help/functions/advanced-io/
---

# Configure the Advanced I/O Function

Next, we will begin coding the Document Processor application by configuring the functions component.

The [functions directory](https://docs.catalyst.zoho.com/en/cli/v1/project-directory-structure/functions-directory) you initialized, `functions/zia_services_function`, contains:

* The `index.js` main function file
* The `catalyst-config.json` configuration file
* node_modules
* `[package.json](https://docs.npmjs.com/files/package.json)` and `[package-lock.json](https://docs.npmjs.com/configuring-npm/package-lock-json.html)` dependency files

In addition to this directory, we will need to add a few sub-directories and files in the `functions/zia_services_function` directory.

We have the tutorial's code in [this git repository](https://github.com/catalystbyzoho/tutorial-catalyst-zia-services). Download it as a ZIP file and extract its contents.

Replace the `index.js` file in your project's `functions/zia_services_function` directory with the one in the extracted zip.

The `functions/zia_services_function` directory from the downloaded ZIP will contain the sub-directories and files mentioned below, in addition to the default function files and dependencies.

* `constants.js` file
* `services` directory
* `pojos` directory
* `handlers` directory
* `errors` directory

Extract these files and add them to your project's function's directory. You can use any IDE of your choice to work with the application’s files.

> **Note :** Please go through the code in this section to make sure you fully understand it.

### Install Express and Multer Frameworks for Node.js

The Node.js function requires two frameworks to be installed for this application. You must install these frameworks to import their packages in your code.

#### express 

This framework is used to enable communication between the client and server end via HTTP requests. To install `Express.js`, navigate to the Node function’s directory (`functions/zia_services_function`) in your terminal and execute the following command:

```sh
npm install express
```

![install-npm](https://catalyst-docs-development.zohostratus.in/images/tutorials/document-processor/nodejs/install-npm.webp)

This will install the Express module and save the dependencies.

#### multer

Multer is middleware used to handle file upload operations from the client end. To install `multer.js`, navigate to the Node function’s directory (`functions/zia_services_function`) in your terminal and execute the following command:

```sh
npm i multer
```

This will install the Multer module and save the dependencies.

![install-multer](https://catalyst-docs-development.zohostratus.in/images/tutorials/document-processor/nodejs/install-multer.webp)

This information will also be updated in the `package.json` file.

![json-details](https://catalyst-docs-development.zohostratus.in/images/tutorials/document-processor/nodejs/json-details.webp)

The function directory is now configured. We can now proceed to configuring the client directory.