1. Storage Type: Mocha is a JavaScript test framework used for testing Node.js applications, whereas MongoDB is a NoSQL database used for storing and retrieving data in a document-oriented database.
2. Purpose: Mocha is primarily used for writing and running tests for Node.js applications, ensuring their quality and performance, while MongoDB is designed for managing large volumes of data, enabling fast retrieval and scalability.
3. Query Language: Mocha uses JavaScript for writing test cases and assertions, while MongoDB utilizes MongoDB Query Language (MQL) for querying and manipulating data stored in the database.
4. Scalability: Mocha focuses on providing a testing environment for JavaScript applications and does not directly influence the scalability of an application, whereas MongoDB is designed to scale horizontally by distributing data across multiple nodes for increased performance and reliability.
5. Data Structure: In Mocha, the focus is on organizing and running test suites and cases, which are defined using JavaScript functions, while MongoDB stores data in collections of documents, which are JSON-like structures that can vary in schema within the same collection.
6. Community Usage: Mocha is widely adopted by the Node.js and JavaScript community for testing applications, while MongoDB is a popular choice among developers for its flexibility in handling unstructured and semi-structured data efficiently.

In Summary, Mocha and MongoDB differ in storage type, purpose, query language, scalability, data structure, and community usage.