How to get the name of the key of an object

Question

How can I get the name of the key name of an object?

In the example I want key to equal a, b and c.

let demo = { "a": valA, "b": valB, "c": valC };

$.each(demo, function (index, val) {
    let key = ??
});

Answer 1

Use Object#keys :

 const demo = { "a": "valA", "b": "valB", "c": "valC" }; const keys = Object.keys(demo); console.log(keys); 

Answer 2

Since you're using ES6 syntax, you have access to the for ... in loop, which can loop through objects.

const demo = { "a": valA, "b": valB, "c": valC };

for (const key in demo) {
  console.log(key);
}

// a
// b