Check if Variable is Empty - Angular 2

Question

How can one check if a variable is empty in Angular 2  I know that there are native ways such as   if  myVar     null   do stuff    but I am looking for something like Angular 1 had such as   if  angular isEmpty variable     do stuff     Q How do check if variable is empty using Angular 2

User · Answer

You can play here with different types and check the output,

Demo

export class ParentCmp {
  myVar:stirng="micronyks";
  myVal:any;
  myArray:Array[]=[1,2,3];
  myArr:Array[];

    constructor() {
      if(this.myVar){
         console.log('has value')     // answer
      }
      else{
        console.log('no value');
      }

      if(this.myVal){
         console.log('has value') 
      }
      else{
        console.log('no value');      //answer
      }


       if(this.myArray){
          console.log('has value')    //answer
       }
       else{
          console.log('no value');
       }

       if(this.myArr){
             console.log('has value')
       }
       else{
             console.log('no value');  //answer
       }
    } 

}

User · Answer

Angular 4 empty data if else  if this data    0    alert  Null data      else     some logic

User · Answer

user Array    1 2 3   if this user length        console log  user has contents      else      console log  user is empty

User · Answer

Ar you looking for that   isEmptyObject obj      return  obj  amp  amp   Object keys obj  length     0         found here   or that    function isEmpty obj        for var key in obj            if obj hasOwnProperty key               return false            return true      found here

User · Answer

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

User · Answer

if  myVariable             mayVariable is not          null        undefined        NaN        empty string             0        false

User · Answer

It depends if you know the given variable Type  If you expect it to be an Object than you could check if myVar is an empty Object like this     public isEmpty myVar   boolean        return  myVar  amp  amp   Object keys myVar  length     0         Otherwise  if   myVar      should do the job

[angular] Check if Variable is Empty - Angular 2

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