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Number Checkers

isPrime​

Determines whether a given number is a prime number using an efficient 6k ± 1 optimization.

Function Signature​

function isPrime(number: number): boolean;

Parameters​

  • number — The integer to evaluate for prime number check.

Returns​

  • true if the number is a prime, otherwise false.

Examples​

isPrime(2);    // true
isPrime(9);    // false
isPrime(17);   // true
isPrime(100);  // false

Aliases​

  • isPrimeNumber

Notes​

  • Uses a fast prime number check based on:
    • Simple divisibility rules for 2 and 3.
    • 6k ± 1 optimization to reduce unnecessary checks.
  • Returns false for all numbers below 2.
  • Ideal for performance on small to moderate integers.

Conclusion​

Use isPrime for fast and reliable checks on prime numbers. Optimized to skip redundant checks for improved efficiency, making it a solid choice for real-time filters, math utilities, or validation routines.

isEven​

Checks if a number is even (divisible by 2).

Function Signature​

function isEven(input: number): boolean;

Parameters​

  • input: The number to check.

Returns​

Returns true if the number is even, otherwise false.

Example​

isEven(4); // true
isEven(3); // false

Aliases​

  • isEvenNumber: Alias for isEven.

isOdd​

Checks if a number is odd (not divisible by 2).

Function Signature​

function isOdd(input: number): boolean;

Parameters​

  • input: The number to check.

Returns​

Returns true if the number is odd, otherwise false.

Example​

isOdd(3); // true
isOdd(4); // false

Aliases​

  • isOddNumber: Alias for isOdd.

isMultiple​

Checks if a number is a multiple of another number.

Function Signature​

function isMultiple(input: number, multipleOf: number): boolean;

Parameters​

  • input: The number to check.
  • multipleOf: The potential multiple.

Returns​

Returns true if input is a multiple of multipleOf, otherwise false.

Example​

isMultiple(10, 5); // true
isMultiple(10, 3); // false

Notes​

  • Returns true when input is 0 and multipleOf is 0 (mathematically undefined case)
  • Handles negative numbers correctly

isPerfectSquare​

Checks if a number is a perfect square.

Function Signature​

function isPerfectSquare(num: number): boolean;

Parameters​

  • num: The number to check.

Returns​

Returns true if the number is a perfect square, otherwise false.

Example​

isPerfectSquare(16); // true
isPerfectSquare(15); // false

isFibonacci​

Checks if a number is part of the Fibonacci sequence.

Function Signature​

function isFibonacci(num: number): boolean;

Parameters​

  • num: The number to check.

Returns​

Returns true if the number is in the Fibonacci sequence, otherwise false.

Example​

isFibonacci(8); // true (Fibonacci sequence: 0, 1, 1, 2, 3, 5, 8...)
isFibonacci(9); // false

Algorithm​

Uses the mathematical property that a number n is Fibonacci if and only if one or both of (5*n^2 + 4) or (5*n^2 - 4) is a perfect square.

Aliases​

  • isParOfFibonacci: Alias for isFibonacci.
  • isParOfFibonacciSeries: Alias for isFibonacci.

areInvalidNumbers​

Checks if any input is not a finite number.

Function Signature​

function areInvalidNumbers(...numbers: number[]): boolean;

Parameters​

  • numbers: Spread of numbers to validate.

Returns​

Returns true if any input is not finite (NaN, Infinity, etc.), otherwise false.

Example​

areInvalidNumbers(1, 2, NaN); // true
areInvalidNumbers(1, 2, 3); // false

Common Use Cases​

  • Validating user input
  • Sanity checking before mathematical operations
  • Data quality verification

Notes​

  • Returns true for:
    • NaN
    • Infinity
    • -Infinity
    • Non-number values (due to type coercion)
  • Returns false for all finite numbers including zero

Aliases​

  • areNumbersInvalid: Alias for areInvalidNumbers.
  • isInvalidNumber: Alias for areInvalidNumbers.
  • isNumberInvalid: Alias for areInvalidNumbers.