JuniorTheoryCommon

What does the program print?

JavaScript

const s = "JavaScript";

console.log(s.slice(4), s.indexOf("a"), s.indexOf("z"));

Script 1 -1

Expecting slice(4) to keep the first four characters: with one argument it returns everything from index 4 to the end, which is Script.
Expecting indexOf to find the last match: it returns the index of the first a, which is 1, and -1 when the text is not found.