JavaScript: Find out if a number is a natural number or not

JavaScript Math: Exercise-12 with Solution

Check Natural Number

Write a JavaScript function to find out if a number is a natural number or not.

Note:
Natural numbers are whole numbers from 1 upwards : 1, 2, 3, and so on ... or from 0 upwards in some area of mathematics: 0, 1, 2, 3 and so on ...
No negative numbers and no fractions.
Test Data:
console.log(is_Natural(-15));
console.log(is_Natural(1));
console.log(is_Natural(10.22));
console.log(is_Natural(10/0));
Output:
false
true
false
false

Visual Presentation:

Sample Solution:

JavaScript Code:

// Define a function named is_Natural that checks if a number is a natural number.
function is_Natural(n) 
{
    // Check if the input is not a number, if so, return 'Not a number'.
    if (typeof n !== 'number') 
        return 'Not a number'; 
    
    // Check if the number is non-negative, an integer, finite, and not Infinity.
    return (n >= 0.0) && (Math.floor(n) === n) && n !== Infinity;
}

// Output the result of checking if -15 is a natural number to the console.
console.log(is_Natural(-15));
// Output the result of checking if 1 is a natural number to the console.
console.log(is_Natural(1));
// Output the result of checking if 10.22 is a natural number to the console.
console.log(is_Natural(10.22));
// Output the result of checking if 10/0 is a natural number to the console.
console.log(is_Natural(10/0));

Output:

false
true
false
false

Flowchart:

Live Demo:

See the Pen javascript-math-exercise-12 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript function that checks if a number is a natural number (non-negative integer) without using built-in functions.
• Write a JavaScript function that validates whether a number is natural and handles both 0-based and 1-based definitions.
• Write a JavaScript function that returns a boolean indicating if an input is a natural number, rejecting fractional or negative values.
• Write a JavaScript function that uses bitwise operators to determine if a number is natural by comparing it to its floored value.

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