Question

Given an object like this:

{ name: "joe" }

I want to get the value “name”. I know I can use the for construct to iterate over the properties in an object, but the objects I’ll be dealing with will always have a single key:value pair, and I won’t know the name of the property. To further illustrate:

var a = { age: 24 };
console.log(myFunc(a)) // Displays "age"

var b = { job: "cook" };
console.log(myFunc(b)) // Displays "job"

Is there anyway to do this without iterating over the object? Also I’d like to do this in pure Javascript. No frameworks/libs involved.

Answer 1

It is good practice to use .hasOwnProperty to ensure you aren’t returning a property from the Object prototype:

function myFunc(obj) {
    for (var prop in obj) {
        if (obj.hasOwnProperty(prop)) return prop;
    }
}