JavaScript (null != someVariable) OR (someVariable != null)

What is the difference between (null != someVariable) and (someVariable != null)? I have seen a lot of people using 'null' first in the comparison. Which one is better than the other and why?

Answer:1

They're equivalent.

However, the first one will cause an invalid assignment error if you mistype != as =. Some people like this as it's rather easy to type = instead of ==, although the former isn't always an accident.

You can see the precise rules of the specification with regard to the == operator on the Annotated ES5.

Answer:2

They evaluate to the same thing, but it is preferable to choose (someVariable != null), because the other way is a Yoda condition. It deals with readability.

Answer:3

The first might be better of someVariable is actually a function with a very long list of arguments. Your intention would be easier to see at first glance. Otherwise, I always use the second.

Answer:4

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