In JavaScript, the Number object provides a set of methods and properties that allow you to work with numeric values. Here’s an overview of the most commonly used functions and properties associated with the Number object:

1. Number Constructors

• Number(value): Converts the argument to a number, returning NaN if it cannot be converted.

  let num = Number("123"); // 123
  let invalidNum = Number("abc"); // NaN
  

2. Static Methods

• Number.isFinite(value): Determines whether the passed value is a finite number.

  console.log(Number.isFinite(123)); // true
  console.log(Number.isFinite(Infinity)); // false
  

• Number.isInteger(value): Checks if the value is an integer.

  console.log(Number.isInteger(10)); // true
  console.log(Number.isInteger(10.5)); // false
  

• Number.isNaN(value): Determines whether the value is NaN. Note that this is different from the global isNaN() function.

  console.log(Number.isNaN(NaN)); // true
  console.log(Number.isNaN("abc")); // false
  

• Number.isSafeInteger(value): Checks if the value is a safe integer, meaning it is an integer within the safe range of -2^53 + 1 to 2^53 - 1.

  console.log(Number.isSafeInteger(9007199254740991)); // true
  console.log(Number.isSafeInteger(9007199254740992)); // false
  

• Number.parseFloat(string): Parses a string argument and returns a floating-point number.

  console.log(Number.parseFloat("3.14")); // 3.14
  

• Number.parseInt(string, radix): Parses a string argument and returns an integer of the specified radix (base).

  console.log(Number.parseInt("10", 2)); // 2 (binary)
  console.log(Number.parseInt("10.5")); // 10
  

• Number.MAX_VALUE: A constant representing the largest positive finite value.

  console.log(Number.MAX_VALUE); // 1.7976931348623157e+308
  

• Number.MIN_VALUE: A constant representing the smallest positive value greater than 0.

  console.log(Number.MIN_VALUE); // 5e-324
  

• Number.NEGATIVE_INFINITY: A constant representing negative infinity.

  console.log(Number.NEGATIVE_INFINITY); // -Infinity
  

• Number.POSITIVE_INFINITY: A constant representing positive infinity.

  console.log(Number.POSITIVE_INFINITY); // Infinity
  

3. Instance Methods

• num.toExponential([fractionDigits]): Returns a string representing the number in exponential notation.

  let num = 123456;
  console.log(num.toExponential(2)); // "1.23e+5"
  

• num.toFixed([digits]): Formats a number using fixed-point notation, rounding if necessary.

  let num = 2.34567;
  console.log(num.toFixed(2)); // "2.35"
  

• num.toPrecision([digits]): Returns a string representing the number to a specified precision.

  let num = 123.456;
  console.log(num.toPrecision(4)); // "123.5"
  

• num.toString([radix]): Converts a number to a string in the specified base (radix).

  let num = 255;
  console.log(num.toString(16)); // "ff" (hexadecimal)
  

• num.valueOf(): Returns the primitive value of a Number object.

  let numObj = new Number(42);
  console.log(numObj.valueOf()); // 42
  

Summary

JavaScript's Number object provides various methods and properties for working with numbers. These include type conversion, parsing, checking conditions (like whether a number is finite, integer, or safe), and formatting numbers into strings. Understanding these functions allows for effective manipulation and validation of numerical data in JavaScript applications.