Subtraction (-)
The subtraction (-) operator subtracts the two operands, producing their difference.
{{EmbedInteractiveExample("pages/js/expressions-subtraction.html")}}
Syntax
x - y
Description
The - operator is overloaded for two types of operands: number and BigInt. It first coerces both operands to numeric values and tests the types of them. It performs BigInt subtraction if both operands become BigInts; otherwise, it performs number subtraction. A {{jsxref("TypeError")}} is thrown if one operand becomes a BigInt but the other becomes a number.
Examples
Subtraction using numbers
5 - 3; // 2
3 - 5; // -2
Other non-BigInt values are coerced to numbers:
"foo" - 3; // NaN; "foo" is converted to the number NaN
5 - "3"; // 2; "3" is converted to the number 3
Subtraction using BigInts
2n - 1n; // 1n
You cannot mix BigInt and number operands in subtraction.
2n - 1; // TypeError: Cannot mix BigInt and other types, use explicit conversions
2 - 1n; // TypeError: Cannot mix BigInt and other types, use explicit conversions
To do subtraction with a BigInt and a non-BigInt, convert either operand:
2n - BigInt(1); // 1n
Number(2n) - 1; // 1