Hello, today we are back with the code smells refactoring series and in this case we are going to talk about code smell calledMagic Numbers, this code smell can be detect when we use a number that lacks the proper semantics.

Cause

Numbers lacking semantics make calculations harder to read.

Example

As we can see in the following example we have2 magic numbers that are quite easy to detect since it is really complex to know what type of calculation we are performing simply by observing these values:4.50 and0.21

functioncalculateTotal(subtotal){consttotal=subtotal+4.50;returntotal+(total*0.21);}

Solution

By extracting both numbers to constants and giving them semantics we can see that the code is much more readable.

constSHIPPING_FEE=4.50;constSALES_TAX=0.21;functioncalculateTotal(subtotal){consttotal=subtotal+SHIPPING_FEE;returntotal+(total*SALES_TAX);}

Benefits

• Improvement the readability and maintainability of the code.
• You will make the next person who needs to go through that part of the code very happy 😋 jiji

Thanks for reading me 😊