Monday, July 15, 2019

JavaScript regular expression trick

Working on a Netcool Impact implementation recently I ran across a feature of JavaScript regular expressions that really impressed me. I'll compare it to a somewhat similar feature/syntax in Perl.

If you need to test a string for a regular expression in Perl, you can do the following:

if ($mystring =~ /my_regular_expression/) ...

That will return true if $string contains the specified regular expression.

In JavaScript, you can invoke the test() method directly on the regular expression (including the leading and trailing "/") with one parameter, which is the string to test. Here's what the equivalent of the above looks like in JavaScript:

if (/my_regular_expression/.test(mystring)) ...

And to test if it doesn't match, the syntax is:

if (!/my_regular_expression/.test(mystring)) ...

That's it. I just thought it was pretty neat.

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