> Does for..in actually require that keys be returned in a specific order? It's complicated. The spec says order of for..in is not defined, browsers all imple

> Does for..in actually require that keys be returned in a specific order? It's complicated. The spec says order of for..in is not defined, browsers all implement the same order, and there keep being attempts to get the spec changed to match. Object.keys, however _does_ have a defined order. https://tc39.github.io/ecma262/#sec-object.keys https://tc39.github.io/ecma262/#sec-object.keys calls https://tc39.github.io/ecma262/#sec-enumerableownpropertynames https://tc39.github.io/ecma262/#sec-enumerableownpropertynam... which calls the [[OwnPropertyKeys]] internal method. For normal objects this is defined at https://tc39.github.io/ecma262/#sec-ordinary-object-internal-methods-and-internal-slots-ownpropertykeys https://tc39.github.io/ecma262/#sec-ordinary-object-internal... which calls https://tc39.github.io/ecma262/#sec-ordinaryownpropertykeys https://tc39.github.io/ecma262/#sec-ordinaryownpropertykeys which completely specifies the order: integer indices in ascending numeric order, then other string-named props in order of property creation, then symbol-named props.