Function firstKey mixed firstKey(object|array a_object) Returns a key of the first element in the a_object argument Source file fcf:fcf.js Namespace fcf Arguments: object|array a_object - A object or array for which a key is obtained Return value: mixed A key of the first element in the a_object argument Examples Example 1 var key = fcf.firstKey({first: "firstValue", second: "secondValue"}); console.log(key); Result: first Example 2 var key = fcf.firstKey(["firstValue", "secondValue"]); console.log(key); Result: 0