Validating arrays in an object of arrays in Javascript

Question

I have a query object that looks like this

{
"regions": [],
"countries": [],
"channels": [],
"partners": [],
"branches": [],
"agents": []

}

After populating the arrays in the object it looks like this.

{
    "regions": [{
        "key": "101",
        "value": "Middle East(XX)"
    }],
    "countries": [],
    "channels": [],
    "partners": [{
        "key": "201",
        "value": "Partner A"
    }, {
        "key": "202",
        "value": "Partner B"
    }],
    "branches": [{
        "key": "401",
        "value": "Bangalore"
    }, {
        "key": "402",
        "value": "Chennai"
    }],
    "agents": [{
        "key": "501",
        "value": "IBM - Metlife"
    }]
}

I'm trying to loop through each of these arrays and determine if I should show the filter component. If any of the arrays in the object holds value, I should be showing the filter component

The code:

case false:
  let itemsInQuery = 0;
  Object.keys(query).forEach((item) => {
  itemsInQuery = query[item].length ? itemsInQuery++ : itemsInQuery;
  })
  itemsInQuery ? this.setState({showBubbles: true, query}) : this.setState({showBubbles: false, query})
  break;

I'm not sure what is wrong here, but itemsInQuery is always zero. Also, is there a better way to do this?

Thank you in advance!

true case code is out of context here and itemsInQuery variable exists only in the false case block — endtoend6
– endtoend6, Commented Jun 11, 2017 at 17:34

AHB · Accepted Answer · 2017-06-11 17:33:18Z

3

If any of the array have items in, you want a boolean to be true?

This sounds like a case for .some which on an array will take a predicate and return true if any item in that array matches the predicate.

const shouldShow = Object.keys(data).some(key => data[key].length > 0)

https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/some

answered Jun 11, 2017 at 17:33

AHB

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4 Comments

endtoend6 Over a year ago

Thank you! Learnt a new method on the array object today :) Cheers!!

endtoend6 Over a year ago

I'm assuming that the loop will come to an end as soon as atleast one of the array is non-empty

trincot Over a year ago

Yes, that is how some works: it stops iterating as soon as one callback returns a truthy value. You can even leave out the > 0.

AHB Over a year ago

Yes correct, it terminates as soon as it finds a true value. Leaving the > 0 is personal preference, I find it a little unreadable without, but whatever suits your style most!

trincot · Accepted Answer · 2017-06-11 17:31:55Z

1

The problem is with this:

itemsInQuery = query[item].length ? itemsInQuery++

The ++ postfix operator returns the current value of itemsInQuery to the rest of the expression (i.e. 0) and then increments that variable to 1. But this is nullified by the assignment that happens afterwards to itemsInQuery which is the value 0.

So don't use ++ in an expression.

You can use this += instead:

itemsInQuery += query[item].length ? 1 : 0;

answered Jun 11, 2017 at 17:31

trincot

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Comments

PeterMader · Accepted Answer · 2017-06-11 17:32:42Z

Does this do what you want?

var data1 = {
    "regions": [{
        "key": "101",
        "value": "Middle East(XX)"
    }],
    "countries": [],
    "channels": [],
    "partners": [{
        "key": "201",
        "value": "Partner A"
    }, {
        "key": "202",
        "value": "Partner B"
    }],
    "branches": [{
        "key": "401",
        "value": "Bangalore"
    }, {
        "key": "402",
        "value": "Chennai"
    }],
    "agents": [{
        "key": "501",
        "value": "IBM - Metlife"
    }]
};

var data2 = {
  "regions": [],
  "countries": [],
  "channels": [],
  "partners": [],
  "branches": [],
  "agents": []
}

function hasEntries (data) {
  for (var index in data) {
    if (Array.isArray(data[index]) && data[index].length) {
      return true;
    }
  }
  return false;
}

console.log(hasEntries(data1));
console.log(hasEntries(data2));

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