Other ways to loop through a JavaScript object?

Question

this code below works well but the ESLint plugin show the warning:"Using 'ForinStatement' is not allowed" so i want to change it to other ways to prevent the warning message:

    let count = 0;
    for (const key in groups) {
      if (Object.prototype.toString.call(groups[key]) === '[object Object]') {
        if ({}.hasOwnProperty.call(groups[key], 'users')) {
          count += groups[key].users.length;
        }
      }
    }

Answer 1

If your goal alone is to avoid errors in your ESLint, i'd suggest using Object.keys(obj).forEach() I usually go with this approach in my own projects.

Pseudo-example:

Object.keys(groups).forEach(key => {
    if (Object.prototype.toString.call(groups[key]) === '[object Object]') {
        if ({}.hasOwnProperty.call(groups[key], 'users')) {
            count += groups[key].users.length;
        }
    }
});

Answer 2

Here are three possible ways of solving this depending on what part of the map you need, the keys, the values or both the key/value pairs.

If you need not only the key, but the value in the map you might choose:

for (const [key, value] of Object.entries(object)) {
  // ...
}

If you only need the keys:

for (const key of Object.keys(object)) {
  // ...
}

Finally, if you only need the values, but not the keys you can use:

for (const value of Object.values(object)) {
  // ...
}