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Multiplication (*)
Baseline
Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The multiplication (*) operator produces the product of the operands.
console.log(3 * 4);
// Expected output: 12
console.log(-3 * 4);
// Expected output: -12
console.log("3" * 2);
// Expected output: 6
console.log("foo" * 2);
// Expected output: NaN
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 multiplication if both operands become BigInts; otherwise, it performs number multiplication. A TypeError is thrown if one operand becomes a BigInt but the other becomes a number.
js
2 * 2; // 4
-2 * 2; // -4
Infinity * 0; // NaN
Infinity * Infinity; // Infinity
Other non-BigInt values are coerced to numbers:
js
"foo" * 2; // NaN
"2" * 2; // 4
js
2n * 2n; // 4n
-2n * 2n; // -4n
You cannot mix BigInt and number operands in multiplication.
js
2n * 2; // TypeError: Cannot mix BigInt and other types, use explicit conversions
2 * 2n; // TypeError: Cannot mix BigInt and other types, use explicit conversions
To do multiplication with a BigInt and a non-BigInt, convert either operand:
js
2n * BigInt(2); // 4n
Number(2n) * 2; // 4