Side effects

- [Narrator] Sometimes a function you create … can have unintended side effects. … Certain side effects can make your functions unreliable … and can make certain bugs harder to find, … so it's important to be aware of them when you have them. … Not all side effects are bad, … you just have to know about them. … We say a function has a side effect when … the given function changes something from outside its scope. … An example of this might be when … a function enables or disables a button. … The function effected something that was outside its scope. … Another side effect is writing to disc. … The disc, outside of the scope of the function, … is changed after the function is run. … What you really want to avoid is unintended side effects. … Let's take a look at some quick programmatic examples. … Jumping into visual studio code, we have a program. … In this first function, we have … a function that has no side effects. … It does not change anything outside of its scope. … It simply returns the input doubled …