🔴 BUG: % is not working properly about calculator HOT 4 CLOSED

Hey I would like to tackle this issue. Do you have more information?

from calculator.

Hey I would like to tackle this issue. Do you have more information?

Sure @arenodi,
before I merged the PR (#18) the percent functionality worked fine but after it, it doesn't work properly.
Example: 100 - 50% = 50

The calculator says 99.5 but it should be 50.
Before I merged #18 this example worked fine and it printed 50

from calculator.

hey @N3v1 , there are a few things to take into consideration:

Lines 73 to 77:

• The if true body will never run, because the typeof of the arg number will always be a string.
• In else body, the percentageToDecimal() function is called and then...

Lines 48 to 50:

• The percentageToDecimal() function receives the string and the parses it with new Decimal().
• new Decimal() returns a decimal and then the decimal is divided by 100.
• percentageToDecimal() then returns the quotient of that operation.

That is, the '50' as a string will trigger the percentageToDecimal() function that will invoke the new Decimal() and be divided by 100, and then returned as 0.5, hence 100 - 0.5 = 99.5.

Fix:

To fix this problem I made a few changes on the code:

1. Add 'math.js' library to parse and evaluate expressions.
   • Lines 28-34
2. Remove library 'decimal.js'.
3. Remove percentageToDecimal() function.
4. Partially refactoring.
   • Lines 43-49

Note: With 'math.js' library the expression is compiled from the way it is typed and then evaluated, eliminating the need to custom parsing it. Also the lib is powerful enough to support future features as advanced arithmetics operations.

I will create a pull request on it.

from calculator.

Thank you @arenodi for your work

from calculator.