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## Resource: About Function Libraries

## Article: About Function Libraries

## Article Link: https://dev.wix.com/docs/studio-two/code-your-site/code-model/function-libraries/about-function-libraries.md

## Article Content:

# About Function Libraries

A [function library](https://dev.wix.com/docs/overview/extensions-framework/site-extensions/function-libraries.md) is a logical component in Studio Two's [component model](https://dev.wix.com/docs/studio-two/code-your-site/code-model/about-the-component-model.md). It gives Editor React Components (ERCs) reusable, stateless logic through editor binding. Unlike a [Data Source](https://dev.wix.com/docs/studio-two/code-your-site/code-model/data-sources/about-data-sources.md), it doesn't hold shared state.

## Anatomy of a function library

In a Studio Two site project, a function library has a manifest and an implementation:

- The **manifest** declares each function's name, parameters, and return type so the editor can offer compatible functions for editor binding.
- The **implementation** exports the functions declared in the manifest.

You add a function library from the **Code** tab through the **Wix Extension Builder**. For the file structure and fields, see [About Function Libraries](https://dev.wix.com/docs/site-extensions/function-libraries/about-function-libraries.md) in Extension References.

## How function libraries work in Studio Two

A function library is connected in the editor and runs on the site:

- **Design time:** A Wix user connects one of the library's functions to a compatible ERC prop in the Studio Two editor.
- **Runtime:** Wix loads the library implementation with the site, calls the connected function, and passes its result to the ERC as a prop.

Wix also uses a built-in function library to convert values during editor binding. For example, it can convert a phone number to rich text when the source and ERC prop use different data types.

## See also

- [Add a Function Library Extension in Studio Two](https://dev.wix.com/docs/studio-two/code-your-site/code-model/function-libraries/add-a-function-library-extension-in-studio-two.md)
- [Build a Function Library in Studio Two](https://dev.wix.com/docs/studio-two/code-your-site/code-model/function-libraries/build-a-function-library-in-studio-two.md)
- [Function Libraries](https://dev.wix.com/docs/overview/extensions-framework/site-extensions/function-libraries.md)
- [Function Library Extension Files and Code](https://dev.wix.com/docs/site-extensions/function-libraries/function-library-extension-files-and-code.md)
- [About the Function Library Manifest](https://dev.wix.com/docs/site-extensions/function-libraries/about-the-function-library-manifest.md)
- [Component Integration Patterns](https://dev.wix.com/docs/studio-two/code-your-site/code-model/component-integration-patterns.md#function-libraries)
- [About Data Sources](https://dev.wix.com/docs/studio-two/code-your-site/code-model/data-sources/about-data-sources.md)