How to convert data to boolean value in javascript

Javascript method to convert data into Boolean values: 1. Use double logical negation, the syntax "!! The value that needs to be converted"; 2. Use the Boolean() function, the syntax "Boolean (the value that needs to be converted)" ".

The operating environment of this tutorial: windows7 system, javascript version 1.8.5, Dell G3 computer.

There are 2 common methods for converting values ​​into Boolean values, as detailed below.

1. Use double logical NOT

A logical NOT operator! You can convert the value into a Boolean value and negate it. Two logical NOT operators can convert The value is converted to the correct boolean value.

console.log(!!0);  //返回false
console.log(!!1);  //返回true
console.log(!!"");  //返回false
console.log(!!NaN);  //返回false
console.log(!!null);  //返回false
console.log(!!undefined);  //返回false
console.log(!![]);  //返回true
console.log(!!{});  //返回true
console.log(!!function(){});  //返回true

2. Use the Boolean() function

Use the Boolean() function to force the value to be converted to a Boolean value.

console.log(Boolean(0));  //返回false
console.log(Boolean(1));  //返回true

[Recommended learning: javascript advanced tutorial]

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