Node.jsの文字列・オブジェクト⇔クエリ文字列への変換

var qs = require("qs");
var querystring = require('querystring');

console.log(qs)
⇒{ stringify: [Function], parse: [Function] }

console.log(querystring )
⇒{
  　unescapeBuffer: [Function: unescapeBuffer],
  　unescape: [Function: qsUnescape],
  　escape: [Function: qsEscape],
  　stringify: [Function: stringify],
  　encode: [Function: stringify],
  　parse: [Function: parse],
  　decode: [Function: parse]
　}

const form_data_qs = qs.stringify({
　　grant_type: 'authorization_code',
　　code: 'code',
　　redirect_uri: 'redirect_uri'
});

console.log(form_data_qs)
⇒grant_type=authorization_code&code=code&redirect_uri=redirect_uri

const form_data_querystring = querystring.stringify({
　　grant_type: 'authorization_code',
　　code: 'code',
　　redirect_uri: 'redirect_uri'
});

console.log(form_data_querystring)
⇒grant_type=authorization_code&code=code&redirect_uri=redirect_uri

const str = querystring.escape('a:b?c$d*1')

console.log(str)
⇒a%3Ab%3Fc%24d*1

const form_data_qs = qs.parse('grant_type=authorization_code&code=code&redirect_uri=redirect_uri')

console.log(form_data_qs)
⇒{
　　grant_type: 'authorization_code',
　　code: 'code',
　　redirect_uri: 'redirect_uri'
}

const form_data_querystring = 'grant_type=authorization_code&code=code&redirect_uri=redirect_uri'

console.log(form_data_querystring)
⇒{
　　grant_type: 'authorization_code',
　　code: 'code',
　　redirect_uri: 'redirect_uri'
}