1Object.entries(obj).forEach(
2    ([key, value]) => console.log(key, value)
3);

1// object to loop through
2let obj = { first: "John", last: "Doe" };
3
4// loop through object and log each key and value pair
5//ECMAScript 5
6Object.keys(obj).forEach(function(key) {
7    console.log(key, obj[key]);
8});
9
10//ECMAScript 6
11for (const key of Object.keys(obj)) {
12    console.log(key, obj[key]);
13}
14
15//ECMAScript 8
16Object.entries(obj).forEach(
17    ([key, value]) => console.log(key, value)
18);
19
20// OUTPUT
21/*
22   first John
23   last Doe
24*/

1let obj = {
2  key1: "value1",
3  key2: "value2",
4  key3: "value3"
5}
6
7Object.keys(obj).forEach(key => {
8    console.log(key, obj[key]);
9});
10// key1 value1
11// key2 value2
12// key3 value3
13
14// using for in - same output as above
15for (let key in obj) {
16  let value = obj[key];
17  console.log(key, value);
18}

1var obj = { first: "John", last: "Doe" };
2
3Object.keys(obj).forEach(function(key) {
4    console.log(key, obj[key]);
5});

1for (var property in object) {
2  if (object.hasOwnProperty(property)) {
3    // Do things here
4  }
5}
6

1var p = {
2    "p1": "value1",
3    "p2": "value2",
4    "p3": "value3"
5};
6
7for (var key in p) {
8    if (p.hasOwnProperty(key)) {
9        console.log(key + " -> " + p[key]);
10    }
11}