ECMAScript 2015，迭代解构表达式 [英] ECMAScript 2015, iterable destructuring expression

问题描述

我正在试验迭代的解构表达式，我想知道为什么一个具体的方式不起作用。也许你可以帮助我。

例如：

  var x，y，myIterable = []; 
 myIterable [Symbol.iterator] = function *（）{
 var count = 0; 
 while（count< 2）{
 yield count ++; 
} 
}; 
 var myArray = Array.from（myIterable）; 
 console.log（（[x，y] = myArray）=== myArray）; 
 // OUTPUT：true 
  

但是，如果我以这种方式尝试它返回 false ，你可以解释为什么吗？

  var x ，y，myIterable = []; 
 myIterable [Symbol.iterator] = function *（）{
 var count = 0; 
 while（count< 2）{
 yield count ++; 
} 
}; 
 var myArray = Array.from（myIterable）; 
 [x，y] = myArray; 
 console.log（[x，y] === myArray）; 
 // OUTPUT：false 
  

解决方案

=== 通过引用比较对象，因为 myArray 和 [x，y] 评估为不同的数组。

  [] === []; // false 
 {} === {}; // false 
  

I am right now experimenting with the iterable destructuring expression, and i am wondering why a specific way does not work. Maybe you can help me on that.

For example that works:

var x, y, myIterable = [];
myIterable[Symbol.iterator] = function* () {
  var count = 0;
  while(count < 2){
    yield count++;
  }
};
var myArray = Array.from(myIterable);
console.log(([x,y] = myArray) === myArray);
//OUTPUT: true

But if i try it this way it returns false, can you explain why?

var x, y, myIterable = [];
myIterable[Symbol.iterator] = function* () {
  var count = 0;
  while(count < 2){
    yield count++;
  }
};
var myArray = Array.from(myIterable);
[x, y] = myArray;
console.log([x,y] === myArray);
//OUTPUT: false

解决方案

=== compares objects by references, since myArray and [x, y] evaluate to a different array.

[] === []; // false
{} === {}; // false

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