This is a playground to test JavaScript. It runs a completely standard copy of Node.js on a virtual server created just for you. Every one of npm’s 300,000+ packages are pre-installed, so try it out:
function cut(str) {
// return ...
}
// Tests
assert(cut("Alexander") == "A");
assert(cut("--łukasz--") == "-");
assert(cut("今日中国") == "今");
assert(cut("☝🏻 I am white") == "☝🏻");
assert(cut("🏴🏴🏴") == "🏴");