if else comparing array to string

Question

I have the following if-else:

if (entity.length > depot.length) {
    for (var i = 0 ; i < entity.length; i++) {
        promises.push(this.getDataFromREST(security, i));
        console.log(entity, depot)
    }
} else {
    for (var i = 0 ; i < depot.length; i++) {
        promises.push(this.getDataFromREST(security, i));
        console.log(entity, depot)
    }
}

Where entity and depot are arrays, but if they are not holding data they = "NULL".

Basically,for the purposes of this explanation, I want the length of "NULL" to be read as 0, or if entity is an array of length 1+ and depot is a string - the condition entity.length > depot.length is met.

so depot could be an array or a string? Did I understand that right? — Jamiec
– Jamiec, Commented Dec 4, 2015 at 11:40

Yeldar Kurmangaliyev · Accepted Answer · 2015-12-04 11:56:10Z

4

If both entity and depot can be either "NULL" string or a valid array, you can simply make a check for "NULL", calculate its length once and use one loop:

var loopLength = Math.max(entity === 'NULL' ? 0 : entity.length, 
                           depot === 'NULL' ? 0 : depot.length);

for (var i = 0 ; i < loopLength; i++) {
    promises.push(this.getDataFromREST(security, i));
    console.log(entity, depot)
}

This loop will run only if at least entity or depot is not "NULL" string and a valid non-empty array.

edited Dec 4, 2015 at 11:56

answered Dec 4, 2015 at 11:39

Yeldar Kurmangaliyev

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7 Comments

notAChance Over a year ago

Ah, excellent. I will try this then I have the time and get back.

Omar Mowafi Over a year ago

This is a cool way of getting the loop length but this will not work in the case that one of them is a string try it out entity="NULL" , depot = [1]. The loopLength should be equal to 1 not 4

Yeldar Kurmangaliyev Over a year ago

@OmarMowafi Oh, now I see, it is a string "NULL". I thought it is a null value. See my update.

Omar Mowafi Over a year ago

@YeldarKurmangaliyev yep that works correctly. My solution also works. I don't understand why I got a down vote :(

Yeldar Kurmangaliyev Over a year ago

@OmarMowafi Probably, because of code duplication. I will give you an upvote if you get rid of it :)

|

Omar Mowafi · Accepted Answer · 2015-12-04 12:03:34Z

2

What you can do is define a function length as follow

function length(s){
   if(s === "NULL") return 0;
   else return s.length;
}

Then write your code as you did but using this function for length

    var entityLength = length(entity);
    var depotLength = length(depot);

    if (entityLength > depotLength) 
       var loopLength = entityLength;
    else
       var loopLength = entityLength;


    for (var i = 0 ; i < loopLength; i++) {
        promises.push(this.getDataFromREST(security, i));
        console.log(entity, depot)
    }

edited Dec 4, 2015 at 12:03

answered Dec 4, 2015 at 11:46

Omar Mowafi

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