Require ('webpack'), cmd error webpack is not defined) when using webpack

Xiaobai is just getting started. I hope a big god can help me answer
. Explain the version: webpack@1.15.0

the code is as follows:
var webpack = require ("webpack");
console.log (" 1111111");
console.log (webpack);
var config = {

entry:{        
    "index":["./src/page/index/index.js"],
    "login":["./src/page/login/index.js"]
},
output:{
    path:"./dist",
    filename:"js/[name].js"
},
externals:{
    "jquery":"window.jQuery"    
},
plugins:{
     new webpack.optimize.CommonsChunkPlugin({
        name : "common",
        filename : "js/base.js"
    }),
}

};
module.exports=config;

-Times error executing webpack order-

Unexpected identifier
E:studyimoocMallmall-fewebpack.config.js:17

             new webpack.optimize.CommonsChunkPlugin({
                 ^^^^^^^

SyntaxError: Unexpected identifier

at NativeCompileCache._moduleCompile (C:\Users\Administrator\node_modules\v8

-compile-cachev8-compile-cache.js:226:18)

at Module._compile (C:\Users\Administrator\node_modules\v8-compile-cache\v8-

compile-cache.js:172:36)

at Object.Module._extensions..js (module.js:663:10)
at Module.load (module.js:565:32)
at tryModuleLoad (module.js:505:12)
at Function.Module._load (module.js:497:3)
at Module.require (module.js:596:17)
at require (C:\Users\Administrator\node_modules\v8-compile-cache\v8-compile-

cache.js:159:20)

I don"t know why. The node environment has been changed several times, and the webpack, which has always reported an error, has been reinstalled many times

.
Mar.06,2021
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-64f5-1b2b770-2ba8c.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b2b770-2ba8c.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?