CODEWITHSUNDEEP
javascriptregex
markzzz
markzzz

Reputation: 47945

Return true/false for a matched/not matched regex

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?

Upvotes: 61

Views: 100131

Answers (5)

SpikePy
SpikePy

Reputation: 101

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

Upvotes: 1

Leslie Hanks
Leslie Hanks

Reputation: 2377

The match method will return null if there is no match.

Upvotes: 26

Megamind Saiko
Megamind Saiko

Reputation: 697

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

Upvotes: 9

Lightness Races in Orbit
Lightness Races in Orbit

Reputation: 385108

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

Upvotes: 164

user113716
user113716

Reputation: 322462

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.

Upvotes: 26

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