#root and #this variables

#root refers to the root context and #this refers to the current evaluation context object. Both are internal variables.

You can also use these variables to access any data model property references available to you. For example, user.name.given, #root.user.name.given, or #this.user.name.given.

#root is useful in the following scenarios:

  • Defining a map key with a base property name’s value, detailed in Maps and objects.
  • Accessing a property from the root context from within array or collection operations, such as projections or filtering, which is outside the current evaluation context. For example, user.memberOfGroupNames.![#root.user.email + ' - ' + #this].

#this is useful within array or collection operations, such as projections or filtering, especially when the collections contain string, boolean, or number types instead of objects. For example, user.memberOfGroupNames.![#string.upperCase(#this)].

Within the projection operator, #this refers to the array element being iterated. If user.memberOfGroupNames is a string array, #this represents each string element being iterated within the projection operator.

Custom library variables

Additional internal variables are available for use in expressions, which are references to the custom libraries covered in Custom library functions.

The following variable references are available to custom libraries:

Reference Description


Function for string-based operations.


Functions for processing arrays.


Functions for parsing and processing date values. All input and output dates are in ISO 8601 format.


Functions using regular expressions.


Functions for crypto operations, such as hashing and more in the future.