Unable to check empty string in if condition using ionic2

Question

I'm Working on search form were i need to check whether city is empty or not. If it is empty then assign Bangalore to it other show the selected city. Here is my If condition

if(this.locations[0].city!="")
{
   var Dynamic = this.locations[0].city;
}
else
{
   Dynamic = "Bangalore";
}

But getting

Runtime Error. cannot read property '0' of undefined.

I am new to Ionic 2.

score 1 · Answer 1 · answered Nov 02 '17 at 14:20

1

modify the IF condition like the below

 if(this.location!=undefined && this.location.length!=0 && this.locations[0].city!="")
    {
       var Dynamic = this.locations[0].city;
    }
    else
    {
       Dynamic = "Bangalore";
    }

answered Nov 02 '17 at 14:20

Prithivi Raj

2,658
1
19
34

Philip Brack · Answer 2 · 2017-11-03T01:43:41.643

1

I might do this

var Dynamic = "Bangalore";
' first to are verifying they are defined
if(this.locations && this.locations[0] && this.locations[0].city && this.locations[0].city.length > 0)
{
  Dynamic = this.locations[0].city;
}

edited Nov 03 '17 at 01:43

answered Nov 02 '17 at 15:11

Philip Brack

1,340
14
26

I think this will fail if `this.locations[0]` is undefined. – Ari Nov 02 '17 at 23:54

score 0 · Answer 3 · answered Nov 02 '17 at 23:49

I suggest you create a function called checkNested for checking the validity of a nested object and use it throughout your app. You can put that in a service.

Also, I think you should define Dynamic outside of the if statement for scoping reasons.

var Dynamic = "Bangalore";
if(this.locations &&  // Checking if this.locations is valid before indexing it
   this.checkNested(this.locations[0], "city") && 
   this.locations[0].city !="" ){
   Dynamic = this.locations[0].city;
}

checkNested function is defined here.

Unable to check empty string in if condition using ionic2

3 Answers3