JavaScript三等于和三变量比较

Question

有人可以解释一下吗？

1 == 1        //true, as expected
1 === 1       //true, as expected
1 == 1 == 1   //true, as expected
1 == 1 == 2   //false, as expected
1 === 1 === 2 //false, as expected
1 === 1 === 1 //false? <--

还有一个布尔逻辑的名称,以这种方式比较两个以上的数字(我称之为"三变量比较",但我认为这是错误的......)

Answer 1

这个表达式:

1 === 1 === 1

被评估为:

(1 === 1) === 1

在评估括号内的表达式后:

true === 1

而且这个表达在逻辑上是错误的.以下表达式true按预期返回:

1 === 1 === true