in web/reactplayer/public/test-harness/js/test-harness.js [190:198]
function copy(o) {
var output, v, key;
output = Array.isArray(o) ? [] : {};
for (key in o) {
v = o[key];
output[key] = (typeof v === "object") ? copy(v) : v;
}
return output;
}