JS - логический
if (typeof variable === "boolean"){
// variable is a boolean
}
Evergreen Tomato
if (typeof variable === "boolean"){
// variable is a boolean
}const dataChecked = true;
const valueCounted = false;function func(){
return true;
}
isBool = func();
console.log(typeof (isBool)); // output - string
let isBool = func();
console.log(typeof (isBool)); // output - boolean// falsy values: false, 0, -0, 0n, null, undefined, NaN, and the empty string ""
console.log(Boolean(false)) // false
console.log(Boolean(0)) // false
console.log(Boolean(-0)) // false
console.log(Boolean(0n)) // false
console.log(Boolean(null)) // false
console.log(Boolean(undefined)) // false
console.log(Boolean(NaN)) // false
console.log(Boolean("")) // false
console.log(typeof Boolean("")) // boolean
// truthy values: true, 1, -1, 1n, -1n, Infinity, -Infinity, " ", {}, []
console.log(Boolean(true)) // true
console.log(Boolean(1)) // true
console.log(Boolean(-1)) // true
console.log(Boolean(1n)) // true
console.log(Boolean(-1n)) // true
console.log(Boolean(Infinity)) // true
console.log(Boolean(-Infinity)) // true
console.log(Boolean(" ")) // true
console.log(Boolean({})) // true
console.log(Boolean([])) // true
console.log(typeof Boolean([])) // booleanconst message = '';
console.log(!! message) // falselet myTrueBool = true;
let myFalseBool = false;