Subtraction Operator ()
Subtracts the value of one expression from another or provides unary negation of a single expression.
number1  number2
number
In Syntax 1, the  operator is the arithmetic subtraction operator used to find the difference between two numbers. In Syntax 2, the  operator is used as the unary negation operator to indicate the negative value of an expression.
For Syntax 2, as for all unary operators, expressions are evaluated as follows:

If applied to undefined or null expressions, a runtime error is raised.

Objects are converted to strings.

Strings are converted to numbers if possible. If not, a runtime error is raised.

Boolean values are treated as numbers (0 if false, 1 if true).
The operator is applied to the resulting number. In Syntax 2, if the resulting number is nonzero, result is equal to the resulting number with its sign reversed. If the resulting number is zero, result is zero.