js中yield和yield*表达式的介绍

const genSomeArr = function* () {

  yield 1;

  yield* [2, 3];

};

const someArr = genSomeArr();

greet.next();   // { value: 1, done: false }

greet.next();   // { value: 2, done: false }

greet.next();   // { value: 3, done: false }

greet.next();   // { value: undefined, done: true }