# Get started with Helper functions functions

Use Journey Optimizer templating language to perform operations on data, such as calculations, data formatting or conversions, conditions, and manipulate them in the context of personalization. Learn personalization syntax guidelines in this page.

➡️ Learn how to use helper functions in this video

Templating language is leveraged in helper functions available in personalization drop-down list of the personalization editor, as below:

In the Journey Optimizer personalization editor, helper functions are grouped into three categories: Functions, Helpers and Operators.

Select a category, to access sub-categories and functions.

Access to sub-categories by clicking the `>`

icon. Select a function by clicking on the `+`

icon: the function is automatically added to the personalization screen.

Click the `...`

icon to view the description of the function and add it to your favorites. Learn more

## Functions functions-helper

### Aggregation and Array Functions

### Date Time Functions date-functions

### Map Functions map-functions

### Math Functions math-functions

### Object Functions object-functions

### String Functions string-functions

## Helpers helper-helper

Helpers are detailed in this page.

## Operators operators-helper

### Arithmetic functions arithmetic-helper

Arithmetic functions are used to perform basic calculations on values.

### Boolean functions boolean-functions

Boolean functions are used to perform boolean logic on different elements.

### Comparison functions comparison-functions

Comparison functions are used to compare between different expressions and values, returning true or false accordingly.

## How-to video video

Learn how to transform personalization values using personalization helper functions and understand different use cases for helper functions.