What syntax is this statement for JavaScript?

what I saw on the Internet:

const randomStr = "hdjrwqpei";
console.log([...randomStr]);

Why is it possible to convert a string to an array after this processing?
output: ["hints," dudes, "jacks," rashes, "winters," Qstocks, "packs," eBay,"i"]

Dec.30,2021
The extension operator of

js (spread).


extension operator (Spread syntax)


is a new syntax for ES6. Please refer to Ruan Yifeng's "introduction to ECMAScript 6" http://es6.ruanyifeng.com/?se.

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MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b3c55a-2ba82.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b3c55a-2ba82.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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