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function combinations(items){     var totalItems    =    items.length;     for(i=0;i         var result    =    Number(i).toString(2);         result    =    ("0000" + result).substr(-4,4);         var combination    =    "";         for(j=0;j             if(result.charAt(j)=="1"){                 combination+=items[j]+",";             }         }           console.log(combination.substring(0,combination.length-1));     } } var items=["a","b","c","d"]; combinations(items); Truth Table based formula deciphering: http://booleanbot.com/

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