JavaScript Number methods are functions that can be performed on numbers. They can be used to convert numbers to different formats, check their properties, and perform other operations.
To use a Number method, simply prefix the method name with the Number
object. For example, to call the isInteger()
method, you would use the following syntax:
Number.isInteger(10);
// returns true
Note that Number methods can only be called on the Number
object, not on individual number variables. For example, the following code will result in an error:
const x = 10;
x.isInteger();
// TypeError: x.isInteger is not a function
Common JavaScript Number Methods
Here is a list of some of the most common JavaScript Number methods:
Number()
: Converts a value to a number. If the value cannot be converted, NaN
is returned.
ParseInt()
: Parses a string and returns an integer number parsed from the string.
ParseFloat()
: Parses a string and returns a floating-point number parsed from the string.
ToExponential()
: Returns a string that represents the exponential notation of the given number.
ToFixed()
: Returns a string that represents a number formatted using fixed-point notation.
ToPrecision()
: Returns a string that represents a number formatted using a specified precision.
ToLocaleString()
: Returns a string that represents the number formatted according to the locale specified by the locales
parameter.
IsInteger()
: Returns true
if the number is an integer, false
otherwise.
IsFinite()
: Returns true
if the number is a finite number, false
otherwise.
IsNaN()
: Returns true
if the number is NaN
, false
otherwise.
Examples
Here are some examples of how to use JavaScript Number methods:
// Convert a string to a numberconst str = "10";
const num = Number(str);
console.log(num);
// 10// Parse a string as an integer
const str = "10.5";
const int = parseInt(str);
console.log(int);
// 10// Parse a string as a floating-point number
const str = "10.5";
const float = parseFloat(str);
console.log(float);
// 10.5// Format a number using exponential notation
const num = 123456789.0123456;
const exp = num.toExponential(2);
console.log(exp);
// 1.23e+8 // Format a number using fixed-point notation
const num = 123456789.0123456;
const fixed = num.toFixed(2);
console.log(fixed);
// 123456789.01// Format a number using a specified precision
const num = 123456789.0123456;
const precision = num.toPrecision(8);
console.log(precision);
// 1.2345679e+8// Format a number according to the locale specified by the `locales` parameter
const num = 123456789.0123456;
const locale = "en-US";
const localeString = num.toLocaleString(locale);
console.log(localeString);
// 123,456,789.01
Conclusion
JavaScript Number methods are a powerful tool for working with numbers. By learning how to use these methods, you can perform a variety of operations on numbers, such as converting them to different formats, checking their properties, and formatting them for display.