Strings comparison not working

Recently, I’m working with typescript angular 7. I try to compare textbox value with some string variabels

text1 = new FormControl("");
String a ="bla";
............
//Somewhere on my coding universe
if(this.text1.value == a){
 alert(“Textbox value same as a”);
}else{
 alert(“Textbox value not same as a”);
}

the result is “Textbox value not same as a”.

I also try

if(this.text1.value.toString() == a){
 alert("Textbox value same as a");
}else{
 alert("Textbox value not same as a");
}

the result is “Textbox value not same as a”.

And also try again

if(this.text1.value.toString().toUpperCase() == a.toUpperCase()){
 alert("Textbox value same as a");
}else{
 alert("Textbox value not same as a");
}

the result is “Textbox value not same as a”.

And also try again!!!!!

if(this.text1.value.match(a)){
 alert("Textbox value same as a");
}else{
 alert("Textbox value not same as a");
}

the result is “Textbox value not same as a”.

if(this.text1.value.trim() == a){
 alert("Textbox value same as a");
}else{
 alert("Textbox value not same as a");
}

The result is “Textbox value same as a”