Borislav Hadzhiev
Sun Oct 31 2021·2 min read
Photo by 邱 严
To get the difference between two numbers, subtract the first number from the
second and pass the result to the Math.abs()
function, e.g.
Math.abs(10 - 5)
. The Math.abs()
function returns the absolute value of a
number.
function getDifference(a, b) { return Math.abs(a - b); } console.log(getDifference(10, 15)); // 👉️ 5 console.log(getDifference(15, 10)); // 👉️ 5 console.log(getDifference(-10, 10)); // 👉️ 20
The Math.abs function returns the absolute value of a number, in other words it returns the number's distance from zero.
Here are some examples:
console.log(Math.abs(-3)); // 👉️ 3 console.log(Math.abs(-3.5)); // 👉️ 3.5 console.log(Math.abs(-0)); // 👉️ 0 console.log(Math.abs(3.5)); // 👉️ 3.5 console.log(Math.abs('-3.5')); // 👉️ 3.5
The Math.abs
method returns the provided number if it's positive or zero and
the negation of the number if it's negative.
Math.abs
function is perfect for this use case.An alternative approach is to use an if
statement.
To get the difference between two numbers, use an if
statement to check
which number is greater, and subtract the lower number from the greater number,
e.g. if (numA > numB) {return numA - numB}
.
function getDifference(a, b) { if (a > b) { return a - b; } return b - a; } console.log(getDifference(10, 15)); // 👉️ 5 console.log(getDifference(15, 10)); // 👉️ 5 console.log(getDifference(-10, 10)); // 👉️ 20
In our if
statement, we check if the first number is greater than the second,
if it is - we subtract the lower number from the greater and return the result.
Otherwise, we know that the numbers are equal, or the second number is greater, and we do the inverse.
Math.abs
function because you won't see the function used very often and not many developers are familiar with it.This could be shortened by using a ternary operator.
To get the difference between two numbers, use a ternary operator to determine
which number is greater, and subtract the lower number and return the result,
e.g. 10 > 5 ? 10 - 5 : 5 - 10
.
const a = 10; const b = -20; const difference = a > b ? a - b : b - a; console.log(difference); // 👉️ 30
A ternary operator is very similar to an if/else
statement.
If the condition evaluates to true
, the expression to the left of the colon
is returned, otherwise the expression to the right of the colon is returned.