# Data Transformer functions

This page describes the additional set of predefined Jsonnet functions for [Data Transformer Script](https://docs.cloud.google.com/application-integration/docs/configure-data-transformer-script-task) task available in Application Integration.


To use the following predefined functions, you must import the `functions` library in your script. Importing the `functions` library lets you use both the standard Jsonnet functions and the predefined **Data Transformer** functions.


Application Integration supports Jsonnet functions library v0.20.0. For information about the Jsonnet standard functions, see [Jsonnet Standard Library](https://jsonnet.org/ref/stdlib.html).

## Jsonnet usage reference

Jsonnet is a purely functional language and its programs are composed of expressions. For information about how to form these expressions, see [Jsonnet Expressions](https://jsonnet.org/ref/language.html#expressions).

## Functions

The following table lists the predefined functions available in Application Integration:

| Functions | Description |
|---|---|
| [Array functions](https://docs.cloud.google.com/application-integration/docs/reference/data-transformer-reference/array-functions-reference) | Functions that operate on arrays. |
| [Aggregate functions](https://docs.cloud.google.com/application-integration/docs/reference/data-transformer-reference/aggregate-functions-reference) | Functions that operate on multiple values. |
| [Hash functions](https://docs.cloud.google.com/application-integration/docs/reference/data-transformer-reference/hash-functions-reference) | Functions that compute hash values. |
| [JSON functions](https://docs.cloud.google.com/application-integration/docs/reference/data-transformer-reference/json-functions-reference) | Functions that operate on JSON values. |
| [Mathematical functions](https://docs.cloud.google.com/application-integration/docs/reference/data-transformer-reference/mathematical-functions-reference) | Functions that perform mathematical operations. |
| [String functions](https://docs.cloud.google.com/application-integration/docs/reference/data-transformer-reference/string-functions-reference) | Functions that operate on string values. |
| [Timestamp functions](https://docs.cloud.google.com/application-integration/docs/reference/data-transformer-reference/timestamp-functions-reference) | Functions that operate on timestamp values. |
| [Utility functions](https://docs.cloud.google.com/application-integration/docs/reference/data-transformer-reference/utility-functions-reference) | Functions that perform utility operations. |
| [XML functions](https://docs.cloud.google.com/application-integration/docs/reference/data-transformer-reference/xml-functions-reference) | Functions that perform XML operations. |
| [Miscellaneous functions](https://docs.cloud.google.com/application-integration/docs/reference/data-transformer-reference/miscellaneous-functions-reference) | Functions that perform miscellaneous operations. |

## Recommendation

- Learn how to add and configure a [Data Transformer Script task](https://docs.cloud.google.com/application-integration/docs/configure-data-transformer-script-task)