Generator

const foo = function* () {
  yield "a";
  yield "b";
  yield "c";
};
let str = "";
for (const val of foo()) {
  str = str + val;
}
console.log(str);
// Expected output: "abc"

function* infinite() {
  let index = 0;
  while (true) {
    yield index++;
  }
}
const generator = infinite(); // "Generator { }"
console.log(generator.next().value); // 0
console.log(generator.next().value); // 1
console.log(generator.next().value); // 2
// ...