Return true/false for a matched/not matched regex
JavascriptRegexJavascript Problem Overview
I have this regex on Javascript
var myS = "00 - ??:??:?? - a";
var removedTL = myS.match(/^(\d\d) - (\?\?|10|0\d):(\?\?|[0-5]\d):(\?\?|[0-5]\d) - (.*)/);
and I need to return "false" if myS is not in that format, true otherwise.
I mean :
var myS = "00 - ??:??:?? - a"; // TRUE
var myS = "00 - ??:?:?? - a"; // FALSE
how can I check if the regex has matched the string or not?
Javascript Solutions
Solution 1 - Javascript
The more appropriate function here might be RegExp.test, which explicitly gives you true or false.
console.log(/lolcakes/.test("some string"));
// Output: false
console.log(/lolcakes/.test("some lolcakes"));
// Output: true
Solution 2 - Javascript
Use a double logical NOT operator.
return !!removedTL;
This will convert to true/false depending on if matches are found.
No matches gives you null, which is converted to false.
One or more matches gives you an Array, which is converted to true.
As an alternative, you can use .test() instead of .match().
/^(\d\d) - (\?\?|10|0\d):(\?\?|[0-5]\d):(\?\?|[0-5]\d) - (.*)/.test( myS );
...which gives you a boolean result directly.
Solution 3 - Javascript
The match method will return null if there is no match.
Solution 4 - Javascript
var myS = "00 - ??:??:?? - a";
var patt = new RegExp("^(\d\d) - (\?\?|10|0\d):(\?\?|[0-5]\d):(\?\?|[0-5]\d) - (.*)");
var removedTL = patt.test(myS);
removedTL will hold a boolean value true if matched, false if not matched
Solution 5 - Javascript
Since I also prefer using match you could do the following workaround to get a Boolean result:
var myS = "00 - ??:??:?? - a"
var removedTL = myS.match(/^(\d\d) - (\?\?|10|0\d):(\?\?|[0-5]\d):(\?\?|[0-5]\d) - (.*)/) != null