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:
Java:
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| public class FloatingPoint { | |
| public static void main(String[] args) { | |
| System.out.println(0.1 + 0.2); | |
| } | |
| } |
Output
0.30000000000000004
So obviously this is not equal to 0.3
Right way to do it : Using BigDecimal
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| 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
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| +(0.1 + 0.2).toFixed(1); |
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
Conclusion
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.
Memoirs of a Software developer 