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Bruce Axtens
Bruce Axtens

Posted on • Edited on

Reversing a string using a Generator

#javascript #programming

So there's this Michiel Hendriks who says, "I'm looking for the next person to one-up this" and so here I am one-upping myself.

Here we reverse the string using a Generator to iterate backwards through the string and hand ball each character to an array that gets .join()ed at the end.

function Bruce_ReverseGenerator(string) { function* reverseGenerator(string) { let str = string; let index = str.length - 1; while (true) yield str.charAt(index--); } let result = []; const gen = reverseGenerator(string); var ch; while (ch = gen.next().value) { result.push(ch); } return result.join(""); }
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Yep, decorated to run in the testing frame and giving surprisingly good results, viz:

C:\TMP>timer.ly /TIMES:1000 Sarah_ForOf 1502.905 ticks Bruce_CharAt 2646.537 ticks Sarah_SplitReverseJoin 2715.699 ticks Bruce_Recursive2 2786.771 ticks Nathanael_SplitReverseJoin 3104.762 ticks Bruce_Recursive1 3112.511 ticks Theophanis_SplitFor 3208.017 ticks Sarah_Reduce 3227.539 ticks Theophanis_SplitFor_Bruced 3706.581 ticks Sarah_Recursive 3810.085 ticks Bruce_ArrayApplyMap 5318.65 ticks Bruce_ReverseGenerator 7354.585 ticks Bruce_MapSortMap 9637.046 ticks Bruce_CharAt2 13913.316 ticks Bruce_RegReverse 490151.264 ticks
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