ES6 RegExp ignoreCase

var re = new RegExp( "string" );

if ( re.ignoreCase ){
   console.log("Test1-ignoreCase property is set");  
} else {
   console.log("Test1-ignoreCase property is not set");  
}
re = new RegExp( "string", "i" );

if ( re.ignoreCase ) {
   console.log("Test2-ignoreCase property is set");  
} else {
   console.log("Test2-ignoreCase property is not set");  
}