Not a JavaScript problem : 0.1 + 0.2 is not equal to 0.3

I have been a back-end developer for some time now but I have decided to learn some front end (JavaScript) stuff too! I know, you must be thinking , it’s 2017, why on earth have I  decided to learn vanilla JavaScript ! May be I should be learning frameworks like ReactJS, Angular, Vue. Sure, why not, that is the idea but I would like to get the basics (JavaScript) right first.

I have been learning the basics of JavaScript and it turns out that quite a number of people mention a few WTF’s with JavaScript . One of them being:  0.1 + 0.2  !== 0.3.  If you are in a state of shock now, well , you should be there for a few more seconds….

Time to come out now ! Well, this is not a problem with JavaScript . Don’t believe me ?

Let us try the same thing in a different language:


public class FloatingPoint {
public static void main(String[] args) {
System.out.println(0.1 + 0.2);

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So obviously this is not equal to 0.3

Right way to do it : Using BigDecimal

import java.math.BigDecimal;
public class FloatingPointCorrected {
public static void main(String[] args) {
System.out.println(new BigDecimal("0.1").add(new BigDecimal("0.2")));

If you tried the same in Python, you will still get the same unexpected result.

Right way to do it in JavaScript : Using toFixed function

+(0.1 + 0.2).toFixed(1);

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Using the toFixed function from Number object helps us in setting the number of digits after the decimal point.It returns a string and hence we need the + operator at the beginning.

So let us not give JavaScript, the language, criminal status for an offense it never committed !

But why is 0.1 + 0.2 ! = 0.3, take a look here : Floating point Math


Let us not find incorrect reasons to criticize the language. Learning JavaScript so far has been a fun learning experience. Of course there have been some WTF moments as well.

JavaScript is powerful ! I urge you to learn it.