Using node 8.4.0:
$ node
> {x, y} = {x: 1, y: 2}
{ x: 1, y: 2 }
>
However, the following errors also non interactive: (the only diff is the semicolon)
$ node
> {x, y} = {x: 1, y: 2};
...
Also in Chrome console:
> {x,y} = {x:1, y:2}
< {x: 1, y: 2}
> {x,y} = {x:1, y:2};
x VM253:1 Uncaught SyntaxError: Unexpected token =
Can anyone explain this?
Clarification
This is not about let, var or cosnt destructuring which works as intended. This is about previously defined variables, (or non strict mode): from chrome console:
> let a, b;
< undefined
> [a, b] = [1, 2];
< >(2) [1, 2]
> a
< 1
> b
< 2
> {a, b} = {a:3, b:4}
< >{a: 3, b: 4}
> a
< 3
> b
< 4
> {a, b} = {a:3, b:4};
x VM1297:1 Uncaught SyntaxError: Unexpected token =
The proper syntax to destructure an object to existing variables is
This allows
{x, y} = {x: 1, y: 2}
to be an expression. Otherwise{x, y}
is interpreted as a block with comma operator, this results inUnexpected token =
error.It works without parentheses and a semicolon in console because it is treated as an expression there. This is efficiently same thing as