1

I have js object that has data which contains numbers. Some of them can be 0. In that case if statement will evaluate those values as an empty strings. Here is example:

var dataObj = {
  "one": 13,
  "two": 0,
  "three": 3
}

$.each(dataObj, function (j, k) {
  if(k){
    console.log('Column: '+k);
  }else{
    console.log('Empty');
  }
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

I'm wondering how this can be prevented? Is there a way to check if value is empty but at the same time not consider 0 as an empty value?

espresso_coffee
  • 5,980
  • 11
  • 83
  • 193
  • 1
    How about `if (k || k === 0)`? – Pointy Dec 12 '18 at 14:57
  • That works but is that a good practice? – espresso_coffee Dec 12 '18 at 14:58
  • 3
    Why wouldn't it be? It's guaranteed to behave in a specific way by the language spec. – Pointy Dec 12 '18 at 14:59
  • Ah, you've stumbled across the loose equality conundrum. Check out this [related post](https://stackoverflow.com/a/359509/2535504). You'll want to use `===` over `==` and depending on what possible valid values (say `null` or `""`) check against those. So `if ( k !== null && k !== "" ) { console.log('Gotcha!'); }` Edit: [here's a good read on truthy and falsy values in JS](https://javascript.info/ifelse#boolean-conversion). – sheng Dec 12 '18 at 15:01
  • 1
    So do not do a truthy check? Check for an empty string? `if (k != '')` – epascarello Dec 12 '18 at 15:03
  • 1
    Is not evaluating as empty string. There are numerous falsy values beyond empty string and `0` is one of them – charlietfl Dec 12 '18 at 15:05

2 Answers2

2

you can change the condition to k || k===0 this mean (as far as i know) it will accept not-undefined, not-null, not-empty and zero int value as a true.

please comment if there anything i can do to improve the answer..

don't forget to checkout my snippet

have a nice day..

var dataObj = {
  "one": 13,
  "two": 0,
  "three": 3,
  "four": null,
  "five": ''
}

$.each(dataObj, function (j, k) {
  // use 'or' operator
  if(k || k===0){
    console.log('Column: '+k);
  }else{
    console.log('Empty');
  }
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
hifebriansyah
  • 341
  • 1
  • 6
0

You can add k==0 with Logical operator (||) as part of the condition which will pass through the condition when the value is 0.

Try

if(k || k == 0){


var dataObj = {
  "one": 13,
  "two": 0,
  "three": 3
}

$.each(dataObj, function (j, k) {
  if(k || k == 0){
    console.log('Column: '+k);
  }else{
    console.log('Empty');
  }
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
Mamun
  • 66,969
  • 9
  • 47
  • 59
  • 1
    Sorry, but this a duplicate of a previous answer (and should be a comment anyway, given that this is a question about good practice, not really about solving a problem) –  Dec 12 '18 at 15:01
  • @ChrisG, why the comment is only under one answer not under another.....voting to close would be more meaningful than commenting. – Mamun Dec 12 '18 at 15:16