Regex match one of two words

I have an input that can have only 2 values apple or banana. What regular expression can I use to ensure that either of the 开发者_StackOverflow中文版two words was submitted?

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This will do:

/^(apple|banana)$/

to exclude from captured strings (e.g. $1,$2):

(?:apple|banana)

Or, if you use a standalone pattern:

apple|banana

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There are different regex engines but I think most of them will work with this:

apple|banana