Check if Variable is Empty - Angular 2
Lets say we have a variable called x, as below:
var x;
following statement is valid,
x = 10;
x = "a";
x = 0;
x = undefined;
x = null;
1. Number:
x = 10;
if(x){
//True
}
and for x = undefined
or x = 0
(be careful here)
if(x){
//False
}
2. String x = null
, x = undefined
or x = ""
if(x){
//False
}
3 Boolean x = false
and x = undefined
,
if(x){
//False
}
By keeping above in mind we can easily check, whether variable is empty, null, 0 or undefined in Angular js. Angular js doest provide separate API to check variable values emptiness.
if( myVariable )
{
//mayVariable is not :
//null
//undefined
//NaN
//empty string ("")
//0
//false
}