Regex - Javascript
- Basic
variable =/value/ => Regular expression/value/g => Make it global, Functions run for all matched values/value/i => Makes it cases insensitivevariable.source => Returns varvariable.exec(S) => Returns the matched value, index, input, length as an objectvariable.test(S) => Returns boolean value true if value is presentS.match(variable) => Returns array of values matched or nullS.search(variable) => Returns index of first match else -1S.replace(variable, "value") => Returns new string with replaced values
- Meta-characters
- $, ^, ., *, ?, +, *, /, ., +
- Character Sets
/va[abc]ue/ => Match if in place of l it contains a, b, c/va[a-z]ue/ => Match if in place of l it contains a to z/va[^abc]ue/ => Match if in place of l it does not contains a, b, c/va[0-9]ue//va[A-Z]ue//[a-z]a[0-9]u[A-Z]/ => We can add many Character sets- Quantifiers
/val{n}ue/ => Match if l comes exactly n times/val{n1,n2}ue/ => Match if l comes n1 to n2 times
- Groupings
/(val){2}ue/ => Match if val comes 2 times
- Character Classes
/va\wue/ => Matches if in place of l we have [A-Za-z0-9_], \W for opposite/va\due/ => Matches if in place of l we have [0-9_], \D for opposite/va\sue/ => Matches if in place of l we have [^ \t\r\n\f\v], \S for opposite, \b for word boundary
- Assertion
/v(?=a)lue/ => Match only if a is after v/v(?!a)lue/ => Match only if a not after v