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Javascript set(-of-string) functions

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Exploits hash keys uniqueness, but in doing so effectively toString()s everything, meaning this should not be used for much beyond strings and perhaps integers.

I used this when I wanted to do some client-side filtering of (integer) identifiers.

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  1. function unique(l) {
  2.   var o=new Object(),ret=[];
  3.   for(i in l){o[l[i]]=1}
  4.   for(k in o){ret.push(k)}
  5.   return ret;
  6. }
  7.  
  8. function union(l1,l2) {
  9.   var o=new Object(),ret=[];
  10.   for(i in l1){o[l1[i]]=1}
  11.   for(i in l2){o[l2[i]]=1}
  12.   for(k in o){ret.push(k)}
  13.   return ret;
  14. }
  15.  
  16. function intersect(l1,l2) {
  17.   var o=new Object(), ret=[];
  18.   for (i in l1) o[l1[i]]=1; //this value is ignored 
  19.   for (i in l2)
  20.     if (o[l2[i]]!==undefined)
  21.        ret.push(l2[i]);
  22.   return ret;
  23. }
  24.  
  25. function except(l1,l2) {
  26.   var o=new Object(), ret=[];
  27.   for (i in l1) o[l1[i]]=1;
  28.   for (i in l2) delete(o[l2[i]]);
  29.   for (i in o) ret.push(i);
  30.   return ret;
  31. }

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