Using regex in Javascript to match special symbols

Question

I am developing a web application for a school. They have terms like course_name and class_name. Think of a course as a template for a class, meaning that a class must inherit most attributes of a course.

Now, the class_name MUST contain the course_name. For example: if course_name is "CSS" then the class_name can be "CSS 101" or "Beginning CSS". Checking for this is easy using regular expressions. I used to use word boundaries \b\b.

However, I recently ran into an issue where the user typed "HTML (Beginner)" as the course_name. \b being a word boundary will no longer work in this case to find a match in the class_name. Can someone please help me on this? My brain is exploding thinking of all the possibilities. The solution should cover most, if not all, scenarios.

-Mark

Maybe I wasn't clear in my last paragraph. Using word boundaries on "HTML (Beginner)", like so: new RegExp("\\b"+course_name+"\\b") doesn't work because of the parenthesis. If no parenthesis was present, then the regular expression would have been flawless... — Mark, Jan 21 '11 at 03:14

score 0 · Answer 1 · edited May 23 '17 at 12:21

First, you'll need to be able to regex-escape the course name. I'm using the code from this question:

course_name.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&')

In order to simulate boundaries when the first/last character in course_name might not be word characters, use the following:

RegExp("(?:^|\\W)" + str + "(?:$|\\W)")

At the beginning, we check for either the beginning of the string or a non-word character, and at the end either the end of the string or a non-word character.

Putting these together, we have:

RegExp("(?:^|\\W)" + course_name.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&') + "(?:$|\\W)")

score 0 · Answer 2 · answered Jan 21 '11 at 02:40

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var courses = "HTML (Beginner)".match(/\w+/g);//gives ["HTML", "Beginner"];
if (courses)//can be null if no word chars found
  for (var i = 0; i < courses.length; i++)
    //look for course[i] in your list of courses

answered Jan 21 '11 at 02:40

Walf

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Like I mentioned above. There are class_names and course_names and class_names MUST ABSOLUTELY contain every single character found in course_names. Doing /\w+/ would only match the words... My question is: How would I match the parenthesis together with the word as well? – Mark Jan 21 '11 at 03:09

score 0 · Answer 3 · answered Jan 21 '11 at 05:43

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You can use 'one or more spaces' as a word separator to extract words and then do a compare right ?

var courses = "HTML (Beginner)".match(/[^\s]+/g); //gives ["HTML", "(Beginner)"]

answered Jan 21 '11 at 05:43

Ravikiran

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Using regex in Javascript to match special symbols

3 Answers3