npm install stc-gbk
const gbk = require('stc-gbk')
stc.workflow({
gbk2utf8: {plugin: gbk, include: {type: 'tpl'}, options: {cov: 'start'}},
// ...
// all other work
// ...
gbkReback: {plugin: gbk, include: {type: 'tpl'}, options: {cov: 'end'}}
});