WebStorm JavaScript 解构赋值
WebStorm JavaScript destructuring assignment
WebStorm 中的以下有效 ES6：
let {a,b} = {a:0,b:0};
{a,b} = {a:2,b:4};
在第二个等号处显示错误："expression expected"。很明显JavaScript设置为ES6.
顺便说一下，添加括号可以消除错误：
let {a,b} = {a:0,b:0};
({a,b} = {a:2,b:4});
这是错误还是 ES6 的一部分？ node编译器好像第一个版本没有问题（没有括号），所以好像不是标准的一部分。
这不是错误，ExpressionStatement 是这样的：
NOTE
An ExpressionStatement cannot start with a U+007B (LEFT CURLY BRACKET) because that might make it ambiguous with a Block. An ExpressionStatement cannot start with the function or class keywords because that would make it ambiguous with a FunctionDeclaration, a GeneratorDeclaration, or a ClassDeclaration. An ExpressionStatement cannot start with async function because that would make it ambiguous with an AsyncFunctionDeclaration. An ExpressionStatement cannot start with the two token sequence let [ because that would make it ambiguous with a let LexicalDeclaration whose first LexicalBinding was an ArrayBindingPattern.
给你的作业加上括号。比如下面是正确的
let foo
({foo = 3} = {foo: 2})
WebStorm 中的以下有效 ES6：
let {a,b} = {a:0,b:0};
{a,b} = {a:2,b:4};
在第二个等号处显示错误："expression expected"。很明显JavaScript设置为ES6.
顺便说一下，添加括号可以消除错误：
let {a,b} = {a:0,b:0};
({a,b} = {a:2,b:4});
这是错误还是 ES6 的一部分？ node编译器好像第一个版本没有问题（没有括号），所以好像不是标准的一部分。
这不是错误，ExpressionStatement 是这样的：
NOTE An ExpressionStatement cannot start with a U+007B (LEFT CURLY BRACKET) because that might make it ambiguous with a Block. An ExpressionStatement cannot start with the function or class keywords because that would make it ambiguous with a FunctionDeclaration, a GeneratorDeclaration, or a ClassDeclaration. An ExpressionStatement cannot start with async function because that would make it ambiguous with an AsyncFunctionDeclaration. An ExpressionStatement cannot start with the two token sequence let [ because that would make it ambiguous with a let LexicalDeclaration whose first LexicalBinding was an ArrayBindingPattern.
给你的作业加上括号。比如下面是正确的
let foo
({foo = 3} = {foo: 2})