The Tor Browser / file revision

 // map.keys() and map.values() return iterators over the key or the value,

 // respectively, of each key-value pair in the map.

 load(libdir + "iteration.js");

 var data = [["one", 1], ["two", 2], ["three", 3], ["four", 4]];

 var m = Map(data);

 var ki = m.keys();

 assertIteratorNext(ki, "one");

 assertIteratorNext(ki, "two");

 assertIteratorNext(ki, "three");

 assertIteratorNext(ki, "four");

 assertIteratorDone(ki, undefined);

 assertEq([k for (k of m.keys())].toSource(), ["one", "two", "three", "four"].toSource());

 assertEq([k for (k of m.values())].toSource(), [1, 2, 3, 4].toSource());

 assertEq([k for (k of m.entries())].toSource(), data.toSource());