NaN; // The Not-A-Number value, also returned as a failure in ...

// ... string-to-number conversions

Infinity and NaN are numbers:

typeof Infinity; // returns "number"

typeof NaN; // returns "number"

These three special values correspond and behave as the IEEE-754

describes them.

The Number constructor (used as a function), or a unary + or -, may be

used to perform explicit numeric conversion:

const myString = "123.456";

const myNumber1 = Number(myString);

const myNumber2 = +myString;

When used as a constructor, a numeric wrapper object is created (though

it is of little use):

const myNumericWrapper = new Number(123.456);

However, NaN is not equal to itself:

const nan = NaN;

console.log(NaN == NaN); // false

console.log(NaN === NaN); // false

console.log(NaN !== NaN); // true

console.log(nan !== nan); // true

// Users can use the isNaN methods to check for NaN

console.log(isNaN("converted to NaN")); // true

console.log(isNaN(NaN)); // true

console.log(Number.isNaN("not converted")); // false

console.log(Number.isNaN(NaN)); // true

In JavaScript, regular numbers are represented with the IEEE 754

floating point type, meaning integers can only safely be stored if the

value falls between Number.MIN_SAFE_INTEGER and Number.MAX_SAFE_INTEGER.

cite-ref-10[10] BigInts instead represent integers of any size, allowing

programmers to store integers too high or low to be represented with the

IEEE 754 format.cite-ref-bigint-mdn-11-0[11]

There are two ways to declare a BigInt value. An n can be appended to an

integer, or the BigInt function can be used:cite-ref-bigint-mdn-11-1[11]

12345

const b = BigInt(12345);

A string in JavaScript is a sequence of characters. In JavaScript,

strings can be created directly (as literals) by placing the series of

characters between double (") or single (') quotes. Such strings must be

written on a single line, but may include escaped newline characters