mini-css-extract-plugin报错

ERROR in ./a.css
Module build failed (from ./node_modules/mini-css-extract-plugin/dist/loader.js):
TypeError: The 'compilation' argument must be an instance of Compilation
    at getCompilationHooks (F:\develop\webpack练习2\node_modules\webpack\lib\javascript\JavascriptModulesPlugin.js:119:10)
    at F:\develop\webpack练习2\node_modules\webpack\lib\javascript\CommonJsChunkFormatPlugin.js:30:19
    at Hook.eval [as call] (eval at create (C:\Users\admin\AppData\Roaming\npm\node_modules\webpack\node_modules\tapable\lib\HookCodeFactory.js:19:10), <anonymous>:7:1)
    at Hook.CALL_DELEGATE [as _call] (C:\Users\admin\AppData\Roaming\npm\node_modules\webpack\node_modules\tapable\lib\Hook.js:14:14)
    at Compiler.newCompilation (C:\Users\admin\AppData\Roaming\npm\node_modules\webpack\lib\Compiler.js:987:30)
    at C:\Users\admin\AppData\Roaming\npm\node_modules\webpack\lib\Compiler.js:1030:29
    at Hook.eval [as callAsync] (eval at create (C:\Users\admin\AppData\Roaming\npm\node_modules\webpack\node_modules\tapable\lib\HookCodeFactory.js:33:10), <anonymous>:6:1)
    at Hook.CALL_ASYNC_DELEGATE [as _callAsync] (C:\Users\admin\AppData\Roaming\npm\node_modules\webpack\node_modules\tapable\lib\Hook.js:18:14)
    at Compiler.compile (C:\Users\admin\AppData\Roaming\npm\node_modules\webpack\lib\Compiler.js:1025:28)
    at Compiler.runAsChild (C:\Users\admin\AppData\Roaming\npm\node_modules\webpack\lib\Compiler.js:495:8)

因为没有packge.json这个文件 所以汇报这个错谨记~