(--)

Baseline

20157

(--) 1

let x = 3;
const y = x--;

console.log(`x:${x}, y:${y}`);
// : "x:2, y:3"

let a = 3;
const b = --a;

console.log(`a:${a}, b:${b}`);
// : "a:2, b:2"

x--
--x

-- 2

x--

--x

--(--x); // SyntaxError: Invalid left-hand side expression in prefix operation

let x = 3;
const y = x--;
// x  2y  3

let x2 = 3n;
const y2 = x2--;
// x2  2ny2  3n

let x = 3;
const y = --x;
// x  2; y = 2

let x2 = 3n;
const y2 = --x2;
// x2  2n; y2  2n


ECMAScript 2027 LanguageSpecification # sec-postfix-decrement-operator

MDN

MDN 2026614

GitHub