You have declared a variable named $$daysInDecember$$ to have a string value of $31.$ When you run this code, it creates a number instead of a string.

const daysInDecember $=31$

What is the most likely cause?

Numeric values can only be a number data type. JavaScript does not support numbers as a string data type.

The variable was created with the keyword const, which will use implicit type casting and make its own interpretation of what the data type should be$.$

JavaScript uses implicit type casting and makes its own interpretations of what the data type should be based on the syntax of the literal value.

JavaScript uses explicit type casting and makes its own interpretations of what the data type should be$.$