Here’s a README.md file for your msgraph-email-reader package, explaining how to use it:

`msgraph-email-reader`

A lightweight TypeScript library for reading emails using Microsoft Graph API. This package supports fetching and managing access tokens and provides an easy-to-use method for retrieving emails from a user's mailbox.

Features

Fetch an access token from Microsoft Identity Platform.
Use the access token to retrieve emails from a user's mailbox via Microsoft Graph API.
Designed for integration with Node.js or Cypress for end-to-end testing.

Installation

Install the package via npm:

npm install msgraph-email-reader

Prerequisites

Microsoft Azure AD App Registration
- Register an application in Azure AD.
- Obtain the following credentials:
  - Client ID
  - Client Secret
  - Tenant ID
- Grant the application the Mail.Read permission.
Node.js
Ensure Node.js version 14.17 or higher is installed.

Usage

1. Import the Package

Import the library into your Node.js or Cypress project:

import {
  fetchAndSetAccessToken,
  setAccessToken,
  readEmails,
} from "msgraph-email-reader";

2. Fetch and Set Access Token

Retrieve and set the access token using your Azure AD credentials:

await fetchAndSetAccessToken(clientId, clientSecret, tenantId);

3. Read Emails

Fetch emails for a specific user based on search criteria:

const emails = await readEmails(emailID, searchText);
console.log("Fetched Emails:", emails);

Examples

Basic Example

import { fetchAndSetAccessToken, readEmails } from "msgraph-email-reader";

const clientId = "your-client-id";
const clientSecret = "your-client-secret";
const tenantId = "your-tenant-id";
const emailID = "user@example.com";
const searchText = "invoice";

(async () => {
  try {
    // Fetch and set access token
    await fetchAndSetAccessToken(clientId, clientSecret, tenantId);

    // Read emails
    const emails = await readEmails(emailID, searchText);
    console.log("Emails:", emails);
  } catch (error) {
    console.error("Error:", error.message);
  }
})();

Cypress Integration

Add the following commands in cypress/support/commands.ts:

import { fetchAndSetAccessToken, readEmails } from "msgraph-email-reader";

Cypress.Commands.add("setAccessToken", () => {
  const clientId = Cypress.env("CLIENT_ID");
  const clientSecret = Cypress.env("CLIENT_SECRET");
  const tenantId = Cypress.env("TENANT_ID");

  return fetchAndSetAccessToken(clientId, clientSecret, tenantId);
});

Cypress.Commands.add("readEmails", (emailID: string, searchText: string) => {
  return readEmails(emailID, searchText);
});

Use the custom commands in your test:

describe("Microsoft Graph API - Read Emails", () => {
  before(() => {
    cy.setAccessToken();
  });

  it("should fetch emails for a user", () => {
    const emailID = "user@example.com";
    const searchText = "invoice";

    cy.readEmails(emailID, searchText).then((emails) => {
      expect(emails).to.be.an("array").and.have.length.greaterThan(0);
      cy.log("Fetched Emails:", emails);
    });
  });
});

API Reference

`fetchAndSetAccessToken(clientId: string, clientSecret: string, tenantId: string): Promise<string>`

Fetches and sets the access token. Must be called before fetching emails.

Parameters:
- clientId: Azure AD application (client) ID.
- clientSecret: Client secret for the Azure AD application.
- tenantId: Azure AD tenant ID.

`setAccessToken(token: string): void`

Sets the access token for reuse.

Parameters:
- token: Access token.

`readEmails(emailID: string, searchText: string): Promise<any[]>`

Fetches emails for a user based on search criteria.

Parameters:
- emailID: Email ID of the user.
- searchText: Search query for filtering emails.

Dependencies

axios: HTTP client for making API requests.

Development

Scripts

Build: Compile TypeScript files to JavaScript.
```
npm run build
```
Test: Run tests using your preferred framework (e.g., Cypress).

License

This project is licensed under the ISC License.

Let me know if you need further adjustments!