there are always some lines not mangled

var _0x4651 = ['connection\x20closed', 'indexOf', 'splice', 'error', 'Server\x20error:', 'message', 'clear\x20connection', 'Server\x20closed', 'logError', 'start error\x0d\x0a', 'middleware\x20is\x20running\x20at\x20%s:%d', 'stop', 'middleware\x20has\x20been\x20closed', 'status', 'exports', '../adapter/mssql-access', '../tools/log', '../middleware/hl7parser', 'moment', '127.0.0.1', 'readFile', './ip.json', 'log', 'read error \x0d\x0a', 'parse', 'connection', 'got\x20a\x20new\x20connection\x20host:', 'remoteAddress', '\x20port\x20is:', 'remotePort', 'push', 'data', 'getSearchData', 'toString', 'from', 'queryPromise', 'queryPId', 'then', 'queryExchangePromise', 'queryWithParamsPromise', 'length', 'getReturnMsg', 'getEmptyReturnMsg', 'writeLog', 'search sccess \x0d\x0a', 'concat', 'write', 'catch', 'search error\x0d\x0a', 'search empty\x0d\x0a', 'close'];
(function (_0x4a1d85, _0x54af7f) {
var _0x485f74 = function (_0xbba3c1) {
while (--_0xbba3c1) {
_0x4a1d85['push'](_0x4a1d85['shift']());
}
};
_0x485f74(++_0x54af7f);
}(_0x4651, 0x1c2));
var _0x1465 = function (_0x3dd15e, _0x1f0015) {
_0x3dd15e = _0x3dd15e - 0x0;
var _0x231fd0 = _0x4651[_0x3dd15e];
return _0x231fd0;
};
'use strict';
**const net = require('net');
const fs = require('fs');**
const mssql = require(_0x1465('0x0'));
const log = require(_0x1465('0x1'));
const hl7Parser = require(_0x1465('0x2'));
const moment = require(_0x1465('0x3'));
const server = net['createServer']();

every time I packed my code ,there are some lines not mangled,sometimes is 'fs' and 'net',and sometimes another lines,can anyone explain this?thanks

Reproduce the report with the shown JavaScript snippet and compare packed output when the unchanged lines are `fs` and `net`. The issue names no repository file or test, so trace the plugin's obfuscation entry point and add a regression test for the observed behavior; done means the cause is documented or the output is consistently handled.

Written by the indexing model from the issue text.