javaScript проверяет, есть ли NAN
function isNaN(x) {
return x !== x;
};
isNaN(NaN);//true
Grepper
function isNaN(x) {
return x !== x;
};
isNaN(NaN);//true// Use isNaN()
// In javascript compare NaN direct alweys return false
let num1 = Number("Vishal");
// This code never work
if(num1 == NaN){ // Direct compare NaN alweys return false so use isNaN() function
....... Your Code .......
}
// This code work
if(isNaN(num1){
.........Your Code .......
}
function milliseconds(x) {
if (isNaN(x)) {
return 'Not a Number!';
}
return x * 1000;
}
console.log(milliseconds('100F'));
// expected output: "Not a Number!"
console.log(milliseconds('0.0314E+2'));
// expected output: 3140
isNaN("Hello") // Returns true
isNaN(345) // Returns false
isNaN('1') // Returns false, since '1' is converted to Number type which results in 0 ( a number)
isNaN(true) // Returns false, since true converted to Number type results in 1 ( a number)
isNaN(false) // Returns false
isNaN(undefined) // Returns trueconst fail = 10 / "zero";
console.log(fail); // NaN (Not a Number)
console.log(isNaN(fail)); // true
console.log(isNaN(10)); // false
console.log(isNaN('10')); // false
console.log(isNaN('blabla')); // true
console.log(isNaN(true)); // false
console.log(1.7976931348623157e+308 * 1000); // Infinity
console.log(1.7976931348623157e+308 * -1000); // - Infinity
console.log(10 / 0); // Infinity
console.log(isFinite(123)); // true