for loop - Iterate over JavaScript object with index

Question

I am trying to loop over a JavaScript object in ES6.

 for (let [value, index] of object) {
    do something with rest
    if (index >= 1) {
       // do something with first item
    }
  }

It works fine, although when I try to use index to get the first item it returns an error in console:

Uncaught TypeError: Invalid attempt to destructure non-iterable instance

Any ideas on how to loop over an object with index? thanks

Answer 1

This is just meant to be an addition to jonas w's solutions.

If you need the key of the current value:

const object = {a:2, b:4, c:6, d:8};

for (const [index, [key, value]] of Object.entries(Object.entries(object))) {
  console.log(`${index}: ${key} = ${value}`);
}

Object.entries(object).forEach(([key, value], index) => {
  console.log(`${index}: ${key} = ${value}`);
});