SOURCE

let a = "abcdefg";
let b = a.substr(1,4);
console.log(a);
console.log(b);


let c = "abcdefg";
let d = c.substring(1,3);
console.log(c);
console.log(d);



let e = "abcdefg";
let f = e.slice(0,4);
console.log(e);
console.log(f);