| Operator | Description | Useage |
|---|---|---|
Logical AND (&&) |
expr1 && expr2 | Returns expr1 if it can be converted to false; otherwise, returns expr2. Thus, when used with Boolean values, && returns true if both operands are true; otherwise, returns false. |
Logical OR (||) |
expr1 || expr2 |
Returns expr1 if it can be converted to true; otherwise, returns expr2. Thus, when used with Boolean values, || returns true if either operand is true. |
Logical NOT (!) |
!expr | Returns false if its single operand can be converted to true; otherwise, returns true. |
Falsy
原文：https://www.cnblogs.com/rosendolu/p/10206347.html