How do you define variables in data weave scripts?101

Saturday 9 March 2024

How do you define variables in data weave scripts?

DataWeave allows you to define two main types of variables:

Global Variables: These are declared in the header section of your script using the var directive. They can be accessed and used throughout the entire script's body.

Here's the syntax:

%dw 2.0
var <variableName> = <expression>
---
<body of your script>

For example:

%dw 2.0
var greeting = "Hello"
---
{
message: greeting ++ " World!"
}

Local Variables: These are declared within the body of your script using the using keyword. Local variables are only accessible within the specific expression or code block where they are defined.

Here's the syntax:

using (<variableName> = <expression>) {
<your code using the variable>
}

For example:

%dw 2.0
---
{
using (fullName = payload.firstName ++ " " ++ payload.lastName) {
greet: "Welcome " ++ fullName
}
}

Here are some additional points to remember about DataWeave variables:

They cannot be reassigned a value after they are initialized.
Their scope is limited to the script where they are defined.
DataWeave also offers predefined variables like now() to access the current timestamp.

For further details and examples, you can refer to the official DataWeave documentation on variables: https://docs.mulesoft.com/dataweave/latest/dataweave-variables