function concatenate_replace(str: string) {
str = str.substring(11).replace("free","FREE").replace("developed","");
return str;
}
let str: string = "TypeScript is a free and open-source high-level programming language developed by Microsoft";
str = concatenate_replace(str);
console.log(str);
/*
run:
"is a FREE and open-source high-level programming language by Microsoft"
*/