--

20157

--

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

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

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

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

x--
--x

x--

--x

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

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

// x = 2
// y = 3

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

// x = 2
// y = 2


ECMAScript 2027 LanguageSpecification # sec-postfix-decrement-operator

MDN

2025716 MDN

GitHub

JavaScript
JavaScript
1. +
2. +=
3. =
4. async function
5. async function*
6. await
7. &
8. &=
9. ~
10. |
11. |=
12. ^
13. (^=)
15. ,
17. --
18. delete
20. /
21. /=
22. ==
23. **
24. **=
26. function*
27. >
28. >=
30. import.meta
  1. import.meta.resolve()
31. import()
32. in
33. ++
34. !=
35. instanceof
36. (<<)
37. <<=
38. <
39. <=
40. &&
41. &&=
42. !
43. ||
44. ||=
45. *
46. *=
47. new
48. new.target
49. null
50. ??=
51. ??
54. ?.
56. %
57. %=
58. >>
59. >>=
60. ...
61. ===
62. !==
63. -
64. -=
65. super
66. this
67. typeof
68. -
69. +
70. >>>
71. >>>=
72. void
73. yield
74. yield*