add: if (!iterable) return []; 
context: var $A = Array.from = function(iterable) {  if (iterable.toArray) {    return iterable.toArray();  } else {    var results = [];    for (var i = 0; i < iterable.length; i++)      results.push(iterable[i]);    return results;  }}
meta: 3974	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/3974/af9adbf17404d887f31369756326b0109da7ae2b/prototype.js/buggy/root/static/js/prototype.js