To create a regular expression the RegExp constructor can be used to create an expression from a string, the other way is to use the regular expression literal syntax. When using the constructor the first argument will be a string of the pattern, and the second argument will contain one or more option flags for the pattern, more on that later. When creating a string representation of the pattern make sure to double up on the backslashes when they are needed, more on backslashes later as well.
There is knowing how to create a pattern, and then there is knowing how to use one. For the most part there are two String prototype methods to be aware of then it comes to this String.match, and String.replace.
I will not be getting into these methods in detail here as I have wrote posts on both the match, and replace methods. However I will be going over a few typical regular expression patterns and examples that I find myself using from time to time in the remainder of this post.
To match the begging of a string.I just need to use the ^ symbol followed be the pattern I want to match for.
The dollar sign symbol can be used to test for a pattern that is to be expected at the end of a string.
A task that comes up often for me is to find a way to match html tags in a string and replace them with something else, or remove them completely. For this I have found that a a negated character set is a good way to go about matching anything and everything that might be in the tag except the ending pointy bracket.
When it comes to the mark down of my blog posts there is from data at the top of each file that is between two instances of three dashes. If I want to match that I have worked out this pattern.
Of course this post does not do regular expressions justice, as there is way more to write about when it comes to them. I will update this post from time to time of course as I keep running into more note worthy things to write about when it comes to them, but it might be best to just keep paying around with them in order to get a sound grasp on regex. There are also other tools at your disposal when it comes to these kinds of tasks, and sometimes it is necessary to make use of those as well rather than depending completely on regex.