* [['hello'],['world','1','2']]
* => [Array(1), Array(3)]
* [['hello'],...[].slice.call(['world','1','2'], 0)]
* => [Array(1), "world", "1", "2"]
* [...['hello'],...[].slice.call(['world','1','2'], 0)]
* => ["hello", "world", "1", "2"]
You can see the effect of adding syntax sugar.... But my level is limited and I can't find any information about... on the Internet. Can someone explain it to me? It’s better to have resources. Thanks.
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
https://developer.mozilla.org...
ES6’s spread operator
http://www.108js.com/article/...
Extension operator