In this article, you’ll learn how to check if a number is a multiple of another in JavaScript by using the remainder operator. Let’s go into detail now.
Check if one number is multiple of another in JavaScript
Using a remainder operator (%)
Syntax: x % y
The remainder operator (or sometimes called the modulo operator) divides two numbers and returns its remainder. By that logic, if a number when divided by another number returns a 0 as its remainder, the former number is therefore a multiple of the latter number.
As such, the code would look something like this:
Code:
const n1 = 10;
const n2 = 2;
const n3 = 3;
function isMultiple(divided, divider) {
return divided % divider === 0; // If the remainder is 0, it's a multiple
}
// Check n1 and n2
if (isMultiple(n1, n2)) {
console.log(`${n1} is a multiple of ${n2}`);
} else {
console.log(`${n1} is NOT a multiple of ${n2}`);
}
// Check n1 and n3
if (isMultiple(n1, n3)) {
console.log(`${n1} is a multiple of ${n3}`);
} else {
console.log(`${n1} is NOT a multiple of ${n3}`);
}Output:
"10 is a multiple of 2"
"10 is NOT a multiple of 3"Checking if a number is a multiple of several other numbers
That’s great, but what if you wanted to check if a number is a multiple of several numbers? For example: How do you check if every number in an array has a number as its multiple or which has that number as a multiple? You could do it manually, but that can be monstrously tedious. An automated method is required and can be found in using a function in combination with rest parameters.
The rest parameter syntax (...) allows a function to have a practically infinite number of parameters, which can then be iterated like an array. Iterating over the parameters can be done with a for...of loop, which specifically iterates over collections like arrays.
Using that method, we can check if a number is a multiple of several numbers; as such:
Code:
function isMultipleOf(product, ...numbers) {
for (const number of numbers) {
// If the remainder is 0, return true
if (product % number === 0) {
return true;
}
}
return false;
}
console.log(isMultipleOf(12, 1, 4, 3, 2, 6));
console.log(isMultipleOf(12, 5));Output:
true
falseAdditionally, you use an array as a parameter, as long as you use a spread syntax (...) with it. The spread syntax takes a collection of items (e.g., arrays, objects) and converts it into a list of arguments (i.e., parameters). A spread syntax has other utilities, which you can read about here. For example:
Code:
function isMultipleOf(product, ...numbers) {
for (const number of numbers) {
// If the remainder is 0, return true
if (product % number === 0) {
return true;
}
}
return false;
}
console.log(isMultipleOf(12, ...[1, 4, 3, 2, 6]));
console.log(isMultipleOf(12, ...[5]));Output:
true
falseAdditionally, if you want the function to instead return every number that has the number as its multiple, you can do like below:
Code:
function isMultipleOf(product, ...numbers) {
const arr = [];
for (const number of numbers) {
// If the remainder is 0, add the number to the list
if (product % number === 0) {
arr.push(number);
}
}
return arr;
}
console.log(isMultipleOf(12, ...[1, 4, 3, 2, 6]));
console.log(isMultipleOf(12, ...[5, 3, 6, 7, 1]));Output:
[1, 4, 3, 2, 6]
[3, 6, 1]Summary
To check if one number is multiple of another in JavaScript, you can use the remainder operator (%) and check whether the number returned is 0 or not. If the number returned is 0, then the number is a multiple of the other.
Maybe you are interested:
- Check If A Number Is Between Two Numbers In JavaScript
- Check if a Number is NaN in JavaScript
- Check if a Number is a Negative Integer in JavaScript
Hello, my name is Davis Cole. I love learning and sharing knowledge about programming languages. Some of my strengths are Java, HTML, CSS, JavaScript, C#,… I believe my articles about them will help you a lot.
Programming Languages: Java, HTML, CSS, JavaScript, C#, ASP.NET, SQL, PHP
