Invoking "toString()" without writing "toString()";

Invoking "toString()" without writing "toString()";
Just add a string to a variable that contains function like

"abc" + f

f.toString will be invoked behind the curtain.

Self Check tampring

var mefunc=function(){

	const str=""+mefunc;
	// Now str contains the code of `mefunc`

	// Use mefunc.charAt(n) to use get a part of the source code.
	// If the source code is tampered with something like console.log,
	// the source code changes so mefunc.charAt(n) will change.
	// Use it to create the output of this function.
	// So tampered function will return a different value.

	return "the result of tampering"
}