Test Method
Testing is important! Returns a boolean
Different Possibilities
Use the alternation or OR operator |
Ignore Case
i flag ignores case
Extract Matches
.match() method to extract
More than the First Match
g flag returns more than the first in a pattern
Match anything - Wildcard Period
Wildcard is . (period) not * (star)
Single Character with Multiple Possibilities
Character Classes - these define a group of characters to match by placing them in square brackets
Letters of the Alphabet
Inside a character set a range of characters can be defined using a hyphen character -
Numbers & Letters of the Alphabet
Hyphen - also works on numbers. Number & letter ranges can be combined in a single character set as well
Single Characters Not Specified
Negated character sets are sets of characters no one wants :(
Characters that Occur One or More Times
+ to match character(s) that appears one or more times in a row
Characters that Occur Zero or More Times
Star *
Lazy Matching
Finds the smallest possible part of the string that satisfies the regex pattern
Criminal Hunt Challenge
Dun dun dun!
Beginning String Patterns
^ outside of a character set ([]) searchs for patterns at the beginning of strings
Ending String Patterns
$ searches the end of strings for patterns
All Letters & Numbers
Shorthand character class \w is the closest to match the alphabet
Everything BUT Letters & Numbers
\W matches that opposite to \w
All Numbers
\d for just digits
All Non-Numbers
\D is all non-numbers
Restrict Usernames Challenge
Usernames be everywhere
Whitespace
\s to find whitespace
Non-Whitespace
\S.... DUH
Upper & Lower Number of Matches
Quantity specifiers {} specify the lower and upper number of patterns
Only the Lower Number of Matches
Leave out the second number, keep the comma
Exact Number of Matches
Just one number no comma
All or None
Possible existence of an element can be checked with ?
Positive & Negative Lookahead
Lookaheads are patterns that tell JS to lookahead in a string for patterns further along
Mixed Group of Characters
To check for groups of characters use ()
Reuse Patterns Using Capture Groups
Search for repeat substrings using capture groups
Capture Gropus to Search & Replace
.replace(exampleRegex, "replace with me")
Remove Whitespace from Start & End
Typical processing
