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JavaScript JavaScript Basics (Retired) Making Decisions with Conditional Statements Build a Random Number Guessing Game

Matthew Beiswenger
Matthew Beiswenger
6,814 Points
Posted by Matthew Beiswenger
Matthew Beiswenger
6,814 Points

== vs. parseInt

In this video, Dave uses parseInt to convert a string to an integer so it can be compared to another integer. Can't the == operator also be used since it will automatically convert an string to an integer? Or is it just best practice to use parseInt to avoid confusion with things like "" == 0?

1 Answer

andren
andren
28,558 Points
andren
andren
28,558 Points

You are correct, == could be used instead. But nowadays use of == is generally discouraged. It can easily lead to unexpected and buggy behavior exactly like you demonstrate with your "" == 0 example.

And beyond that it's also in most cases a bad idea to store pure numbers in a string. As it can lead to buggy behavior if said number ever ends up being used in a mathematical operation or something like that.

If you use the + operator on a number stored in a string for example then it will be concatenated (glued together) with the other thing you specify instead of having addition performed on it. "5" + 5 equals "55" for example. Potentially running into unexpected behavior like that is something you should go out of your way to avoid.