I have an array of objects where some keys return an empty value. When an empty value appears I'd like to return that key as a string.

For example this array:

'products': [{                           
        'name': 'Test product',     
        'id': '',
        'price': '',
        'brand': 'AwesomeBrand',
        'colour': 'Gray',
        'quantity': 1
       },
       {
        'name': '',
        'id': '123',
        'price': '',
        'brand': 'AwesomeBrand',
        'colour': 'Black',
        'quantity': 1
       }]

In the example above I want to return the following:

'id, price, name'

I've tried the following that kind of does the job. However, it still returns as an array. Then I JSON.strigify it but that returns an ugly string. I tried replacing/RegEx cleaning it however, the program I'm using uses a Sandboxed Version of JavaScript so some features are not accessible.

I'm struggling to grasp the concept of accessing keys and values in an array of objects. So that is part of my problem.

var productArray = ecomValues || [];
var emptyArray = [];

var output = productArray.reduce(function (previousValue, currentValue, currentIndex) {
  var keys = Object.keys(currentValue).filter(function (key) {
    return !currentValue[key];/  });

  if (keys.length) {
    previousValue[currentIndex] = keys;
  }

  return previousValue;
}, {});

var emptyValues = output;
emptyArray.push(emptyValues);

Anyone that can help me with my issue?

CodePudding user response：

We can use reduce() to create an array with all the keys that are empty

1. To find the empty keys we can use this for an example

2. Then, we remove all duplicate keys

3. And join() the array to a string

const data = {'products': [{'name': 'Test product', 'id': '', 'price': '', 'brand': 'AwesomeBrand', 'colour': 'Gray', 'quantity': 1 }, {'name': '', 'id': '123', 'price': '', 'brand': 'AwesomeBrand', 'colour': 'Black', 'quantity': 1 }]};

const emptyKeys = data.products.reduce((prev, cur) => 
    [ ...prev, ...Object.keys(cur).filter((key) => !cur[key]) ], [])
    .filter((v, i, a) => a.indexOf(v) === i)
    .join(', ');

console.log(emptyKeys);

id, price, name

CodePudding user response：

Iterate products with Array.flatMap(), filter out all keys with non-empty values, and then make the array unique by using a Set, and spreading back to an array:

const products = [{ name: 'Test product', id: '', price: '', brand: 'AwesomeBrand', colour: 'Gray', quantity: 1 }, { name: '', id: '123', price: '', brand: 'AwesomeBrand', colour: 'Black', quantity: 1 }]

const result = [...new Set(products.flatMap(
  obj => Object.keys(obj)
    .filter(key => obj[key] === '')
))]

console.log(result);

CodePudding user response：

You could iterate the array and get the keys and add the keys if a falsy value is found.

const
    products = [{ name: 'Test product', id: '', price: '', brand: 'AwesomeBrand', colour: 'Gray', quantity: 1 }, { name: '', id: '123', price: '', brand: 'AwesomeBrand', colour: 'Black', quantity: 1 }],
    empty = Array.from(products.reduce((s, o) => {
        Object.keys(o).forEach(k => {
            if (o[k] === '') s.add(k);
        });
        return s;
    }, new Set));

console.log(empty.join(', '));

A solution without Set.

const
    products = [{ name: 'Test product', id: '', price: '', brand: 'AwesomeBrand', colour: 'Gray', quantity: 1 }, { name: '', id: '123', price: '', brand: 'AwesomeBrand', colour: 'Black', quantity: 1 }],
    empty = Array.from(products.reduce((r, o) => {
        Object.keys(o).forEach(k => {
            if (o[k] === '' && !r.includes(k)) r.push(k);
        });
        return r;
    }, []));

console.log(empty.join(', '));

CodePudding user response：

You can simply achieve that by iterating the array using Array.forEach() along with Object.keys() method.

Demo :

const products = [{                           
  'name': 'Test product',     
  'id': '',
  'price': '',
  'brand': 'AwesomeBrand',
  'colour': 'Gray',
  'quantity': 1
}, {
  'name': '',
  'id': '123',
  'price': '',
  'brand': 'AwesomeBrand',
  'colour': 'Black',
  'quantity': 1
}];

const res = [];

products.forEach((obj) => {
    Object.keys(obj).forEach((objKey) => {
    !obj[objKey] ? res.push(objKey) : ''
  })
})

// Remove duplicate elements from an array
console.log([...new Set(res)]);