Counterintuitive behavior in object assignment

Ask the community
,
1

Dear, probably this is trivial for you… Can you explain or link a good article explaining this counterintuitive behavior in object assignment (see below). Thanks

function changeKey ( newValue , obj ) {
obj [ ‘key’ ] = newValue ;
return obj ;
}

**const**  obj1  = {  'key' :  'oldValue'  }; 
console . log (  obj1 );                      //key: 'oldValue' 

**var**  obj2  = {}; 
obj2 [ 'key' ] =  obj1 [ 'key' ]; 

obj2  =  changeKey (  'newValue' ,  obj2  ); 
console . log ( obj2 );                       //key: 'newValue' 
console . log ( obj1 );                       //key: 'oldValue' 

**var**  obj3  =  obj1 ; 

obj3  =  changeKey (  'newValue' ,  obj3  ); 
console . log ( obj3 );                       //key: 'newValue' 
console . log ( obj1 );                       //key: 'newValue'
  • minimal detail edited not affecting the issue