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| Viewing: https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Operators/Logical_NOT | [Back] [Original] |
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const a = 3;
const b = -2;
console.log(!(a > 0 || b > 0));
// Expected output: false
!expr
true false true
false
nullNaN0"" '' ``undefined ! !! Boolean
!
!true; // !t returns false
!false; // !f returns true
!""; // !f returns true
!"Cat"; // !t returns false
!!!!true; // !!truthy returns true
!!{}; // !!truthy returns true: any object is truthy...
!!new Boolean(false); // ...even Boolean objects with a false .valueOf()!
!!false; // !!falsy returns false
!!""; // !!falsy returns false
!!Boolean(false); // !!falsy returns false
!!bCondition
bCondition
| ECMAScript 2027 LanguageSpecification # sec-logical-not-operator |
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