object-property – Tarik Billa

Javascript: Checking if an object has no properties or if a map/associative-array is empty [duplicate]

August 2, 2023 by Tarik

Try this: function isEmpty(map) { for(var key in map) { if (map.hasOwnProperty(key)) { return false; } } return true; } Your solution works, too, but only if there is no library extending the Object prototype. It may or may not be good enough.

Detecting an undefined object property

August 22, 2022 by Tarik

The usual way to check if the value of a property is the special value undefined, is: if(o.myProperty === undefined) { alert(“myProperty value is the special value `undefined`”); } To check if an object does not actually have such a property, and will therefore return undefined by default when you try to access it: if(!o.hasOwnProperty(‘myProperty’)) … Read more