how do i use for in javascript code example

Example 1: javascript for

let str = "";

for (let i = 0; i < 9; i++) {
  str = str + i;
}

console.log(str);
// expected output: "012345678"

Example 2: for in javascript

const object = { a: 1, b: 2, c: 3 };

for (const property in object) {
  console.log(`${property}: ${object[property]}`);
}

// expected output:
// "a: 1"
// "b: 2"
// "c: 3"