for ... in with index javascript code example

Example 1: javascript object array iteration

let obj = {
  key1: "value1",
  key2: "value2",
  key3: "value3"
}

Object.keys(obj).forEach(key => {
  let value = obj[key];
  //use key and value here
});

Example 2: javascript enumerate with index

const iterable = [...];
for (const [index, elem] in iterable.entries()) {
  f(index, elem);
}

// or
iterable.forEach((elem, index) => {
  f(index, elem);
});