how to through the object of array in javascript code example

Example 1: javascript loop through object example

var person={
 	first_name:"johnny",
  	last_name: "johnson",
	phone:"703-3424-1111"
};
for (var property in person) {
  	console.log(property,":",person[property]);
}

Example 2: javascript loop through array of objects

var arr = [{id: 1},{id: 2},{id: 3}];

for (var elm of arr) {
  console.log(elm);
}