Case and Negation in JavaScript Regular Expressions

You can match the whole available string, using the '^' with the '$' characters. The following code produces a match:

/^be.*end$/.test("beginning and end")

The following code also produces a match:

/^be.*end$/.test("beginning with end")

The available string of the first case is "beginning and end." The available string of the next case is "beginning with end." The difference occurs in the word in the middle.

The regexp content of both cases is the same. The content begins with '^' and ends with '$'. The regexp indicates that the available string to be matched has to begin with "de," followed by any character, any number of times; and the available string has to end with "end."

The period stands for any character. The '*' following the period in the regexp means that any character can reoccur in sequence. So '.*' in regexp tells it to match any character any number of times (including zero times).

Note: all along, when we say match, we are actually searching the available string for a sub-string, represented by the content of the regexp. However, when you are matching the whole available string, the regexp represents the whole string.

So you can now match a whole string. By the time you complete this series, you will be able to match an entire available string that has particular words within the string. I will not show you how to do that. It will be an exercise for you. You will simply need to combine many of the techniques I explain in this series.

We will take a break here and continue in the next part of the series.