javascript - javascript 中的两个对象/数组会巧合吗？

Question

假设我有数组 a。

var a = [1,2,3];

然后是数组b。

var b = [1,2,3];

a == b 是否有可能返回 true？即使是百万分之一。 (我知道通常 a == b 为假，但我想知道它是否有可能为真。)

Answer 1

规范的相关部分是11.9.3 The Abstract Equality Comparison Algorithm :

The comparison x == y, where x and y are values, produces true or false. Such a comparison is performed as follows:

1. If Type(x) is the same as Type(y), then
   1. If Type(x) is Undefined, return true.
   2. If Type(x) is Null, return true.
   3. If Type(x) is Number, then
      1. If x is NaN, return false.
      2. If y is NaN, return false.
      3. If x is the same Number value as y, return true.
      4. If x is +0 and y is −0, return true.
      5. If x is −0 and y is +0, return true.
      6. Return false.
   4. If Type(x) is String, then return true if x and y are exactly the same sequence of characters (same length and same characters in corresponding positions). Otherwise, return false.
   5. If Type(x) is Boolean, return true if x and y are both true or both false. Otherwise, return false.
   6. Return true if x and y refer to the same object. Otherwise, return false.

(强调我的。)

所以你的问题的答案是否定的。 a == b 仅当它们实际上是同一个对象时才返回 true。