Convert string to number with JavaScript
Been working through swapping a MySQL library recently to prepare for a major database upgrade. The old library would return the results from function like AVG and SUM as a number. The new library, not so much.
MySQL natively returns those values as strings, which I can applaud the library for respecting. Coming from a library that was doing the conversion automatically left us with a ton of broken tests and code to patch.
Fortunately, it's not that hard to convert a string to a number. There's also multiple ways to approach the problem, based on what type of number you're expecting to get back.
String to integer
If you are expecting a string to be an integer, you can use the parseInt function, explicitly letting it know the base you're working with:
> parseInt('12345', 10);12345If you were to pass in a number with a decimal, the function will still work, but it will strip everything after the decimal point. No rounding occurs either:
> parseInt('12345.67', 10);12345String to decimal
If you are working with numbers with decimals you can use the Number constructor:
> Number(12345.67);12345.67This also works with integers, so this tends to be my preferred method to convert strings to numbers:
> Number('12345');12345