JavaScript类型转换：(true \u0026\u0026 1)vs(true | | 1)

JavaScript是非严格类型的 Java 语言,例如.

我们知道,它会根据上下文来转换结果的值：

“2”“3”结果“23”

“2”*“3”结果6

这是非常明确的,可以理解.

我只是尝试了以下表达式,并被困惑：

真实&& 1结果1

真|| 1个结果是真的

为什么第一个给数字和第二个给出布尔值？

考虑到JavaScript转换规则,我希望在这两种情况下都会得到布尔值,因为表达式的布尔上下文.

The && operator is commonly called logical and. It can also be called  guard. If the first operand is false, null, undefined, “” (the empty  string), or the number 0 then it returns the first operand. Otherwise,  it returns the second operand. This provides a convenient way to write  a null-check:

var value = p && p.name; /* The name value will only be retrieved from
p if p has a value, avoiding an error. */

The || operator is commonly  called logical or. It can also be called default. If the first operand  is false, null, undefined, “” (the empty string), or the number 0,  then it returns the second operand. Otherwise, it returns the first  operand. This provides a convenient way to specify default values:

value = v || 10; /* Use the value of v, but if v doesn't have a value,
use 10 instead. */