Superagent sends post to gbk-encoded websites, causing problems with garbled codes.

  node.js, question
const superagent = nodeRequire('superagent');
 const superagentCharset = nodeRequire('superagent-charset');
 superagentCharset(superagent).post(obj.url).send(post_data).set('Content-Type', 'application/x-www-form-urlencoded;'  ).set("Cookie", obj.cookie).charset().end(function(err,res) {

Send Chinese parameters to other websites, such as comments. The Chinese language has changed into a random code.

I tried to convert Chinese parameters into gbk. Not even.

Two years later, I encountered this problem again. Baidu did a search and found a similar problem. The questioner was myself.
In the end, I solved the problem and recorded it so as not to make the same mistake again:

Step 1: First convert post data into gbk (omitted)

Step 2: Specify the code when sending post submission