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Variables

Access variables​

Access the value of a variable by its variable name.

a + b

If the value of the variable is a context, a context entry can be accessed by its key.

a.b

If no variable exists with the given name, the expression returns null.

tip

Use a null-check if the variable can be null or is optional.

a != null and a.b > 10

Variable names​

The name of a variable can be any alphanumeric string including the _ symbol. For a combination of words, it's recommended to use the camelCase or the snake_case format. The kebab-case format is not allowed because it contains the operator -.

When accessing a variable in an expression, keep in mind the variable name is case-sensitive.

Restrictions of a variable name:

  • It may not start with a number (e.g. 1stChoice is not allowed; you can use firstChoice instead).
  • It may not contain whitespaces (e.g. order number is not allowed; you can use orderNumber instead).
  • It may not contain an operator (e.g. +, -, *, /, =, >, <, ?, .).
  • It may not be a literal (e.g. null, true, false) or a keyword (e.g. function, if , then, else, for, return, between, instance, of, not, in, and, or, some, every, satisfies).

Escape variable names​

Camunda Extension

If a variable name or a context key contains any special character (e.g. whitespace, dash, etc.) then the name can be wrapped into single backquotes/backticks (e.g. `foo bar`).

`first name`

`tracking-id`

order.`total price`
tip

Use the get value() function to retrieve the context value of an arbitrary key.

get value(order, "total price")