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copied!<p>mine uses a single regex to look for cases where trimming is necessary, and uses that regex's results to determine desired substring bounds:</p> <pre><code>var illmatch= /^(\s*)(?:.*?)(\s*)$/ function strip(me){ var match= illmatch.exec(me) if(match && (match[1].length || match[2].length)){ me= me.substring(match[1].length, p.length-match[2].length) } return me } </code></pre> <p>the one design decision that went into this was using a substring to perform the final capture. s/\?:// (make the middle term capturing) and and the replacement fragment becomes:</p> <pre><code> if(match && (match[1].length || match[3].length)){ me= match[2] } </code></pre> <p>there's two performance bets I made in these impls:</p> <ol> <li><p>does the substring implementation copy the original string's data? if so, in the first, when a string needs to be trimmed there is a double traversal, first in the regex (which may, hopefully be partial), and second in the substring extraction. hopefully a substring implementation only references the original string, so operations like substring can be nearly free. <em>cross fingers</em></p></li> <li><p>how good is the capture in the regex impl? the middle term, the output value, could potentially be very long. i wasn't ready to bank that all regex impls' capturing wouldn't balk at a couple hundred KB input capture, but i also did not test (too many runtimes, sorry!). the second ALWAYS runs a capture; if your engine can do this without taking a hit, perhaps using some of the above string-roping-techniques, for sure USE IT!</p></li> </ol>

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