Create user-defined functions with the SDK

  • 3 minutes

The Scripts property in the Microsoft.Azure.Cosmos.Container class contains a CreateUserDefinedFunctionAsync method that is used to create a new user-defined function from code.

Note

The next set of examples assume that you already have a container variable defined.

To start, define the JavaScript function for the UDF in a string variable.

string udf = @"function addTax(preTax) {
    return preTax * 1.15;
}";

Tip

Alternatively, you can use file APIs such as System.IO.File to read a function from a *.js file.

Next, create an object of type Microsoft.Azure.Cosmos.Scripts.UserDefinedFunctionProperties with the Id and Body properties set to the unique identifier and content of the UDF, respectively.

UserDefinedFunctionProperties properties = new()
{
    Id = "addTax",
    Body = udf
};

Finally, invoke the CreateUserDefinedFunctionAsync method of the container variable to create a new UDF passing in the properties composed earlier.

await container.Scripts.CreateUserDefinedFunctionAsync(properties);