Firefox includes a non-standard JavaScript extension that makes regular expressions callable as functions. This serves as a shorthand for calling a regex's exec method. For example, in Firefox /regex/("string") is equivalent to /regex/.exec("string"). Early ECMAScript 4 proposals indicated this functionality would be added to the ES4 specification, but subsequent discussion on the ES4-discuss mailing list [...]

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Certain operations are computationally expensive, but because their results might change over time or due to outside influences, they don't lend themselves to typical memoization — take for example getElementsByClassName. Here's a JavaScript timed memoization decorator / higher-order-function I made to help with these cases, which accepts an optional expiration argument in milliseconds. function memoize (functor, [...]

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Not all shorthand character classes and other JavaScript regex syntax is Unicode-aware. In some cases it can be important to know exactly what certain tokens match, and that's what this post will explore. According to ECMA-262 3rd Edition, \s, \S, ., ^, and $ use Unicode-based interpretations of whitespace and newline, while \d, \D, \w, \W, [...]

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Since I've seen tons of password validation help requests on regexadvice.com (where I hang out from time to time), I've written up a more general-purpose JavaScript password validation function. It's reasonably straightforward, and covers the validation requirements I've most frequently encountered. Plus, if it doesn't handle your exact needs, its functionality can be augmented by [...]

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When I posted my matchRecursive function the other day (which allows easily matching nested constructs), I noted that it could easily be modified to work with a regex pattern rather than a string as the format argument. After looking at it again, I realized the conversion wouldn't be entirely straightforward, so I've gone ahead and [...]

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