Vue added let to script to report an error - Codes Helper

problem description

defining the let variable at the top of the script block of the component will report an error, but there is no problem to change it to var, there is no problem with the definition of let in the method, and the same error is reported for other component let definitions. I beg you, there is something wrong with this. I haven"t found it either. I"ve never encountered such a problem before. Thank you very much

the environmental background of the problems and what methods you have tried

invalid vue-loader version replacement

related codes

/ / Please paste the code text below (do not replace the code with pictures)

< script >
import Item from". / item.vue"
import Tabs from". / tabs.vue"
let id=1;
export default {

data(){
    return{
        todo:{
            id:0,
            content:"this is todo",
            completed:false
        },
        filter:"all"
    }
},
components:{
    Item,
    Tabs
},
methods:{
    addTodo:function(){
      let a=1;
      //id=1;
    }
}

}
< / script >

what result do you expect? What is the error message actually seen?

ERROR in. / nodewritten modulesAccording to BabelMurloaderapapache.Cache.According to
Module build failed: TypeError: Cannot read property "bindings" of null

, SRC _

at Scope.moveBindingTo (C:\Users\Sercl\Desktop\todox\node_modules\@babel\traverse\lib\scope\index.js:867:13)
at BlockScoping.updateScopeInfo (C:\Users\Sercl\Desktop\todox\node_modules\babel-plugin-transform-es2015-block-scoping\lib\index.js:364:17)
at BlockScoping.run (C:\Users\Sercl\Desktop\todox\node_modules\babel-plugin-transform-es2015-block-scoping\lib\index.js:330:12)
at PluginPass.BlockStatementSwitchStatementProgram (C:\Users\Sercl\Desktop\todox\node_modules\babel-plugin-transform-es2015-block-scoping\lib\index.js:70:24)
at newFn (C:\Users\Sercl\Desktop\todox\node_modules\@babel\traverse\lib\visitors.js:193:21)
at NodePath._call (C:\Users\Sercl\Desktop\todox\node_modules\@babel\traverse\lib\path\context.js:53:20)
at NodePath.call (C:\Users\Sercl\Desktop\todox\node_modules\@babel\traverse\lib\path\context.js:40:17)
at NodePath.visit (C:\Users\Sercl\Desktop\todox\node_modules\@babel\traverse\lib\path\context.js:88:12)
at TraversalContext.visitQueue (C:\Users\Sercl\Desktop\todox\node_modules\@babel\traverse\lib\context.js:118:16)
at TraversalContext.visitSingle (C:\Users\Sercl\Desktop\todox\node_modules\@babel\traverse\lib\context.js:90:19)
at TraversalContext.visit (C:\Users\Sercl\Desktop\todox\node_modules\@babel\traverse\lib\context.js:146:19)
at Function.traverse.node (C:\Users\Sercl\Desktop\todox\node_modules\@babel\traverse\lib\index.js:94:17)
at traverse (C:\Users\Sercl\Desktop\todox\node_modules\@babel\traverse\lib\index.js:76:12)
at transformFile (C:\Users\Sercl\Desktop\todox\node_modules\@babel\core\lib\transformation\index.js:88:29)
at runSync (C:\Users\Sercl\Desktop\todox\node_modules\@babel\core\lib\transformation\index.js:45:3)
at runAsync (C:\Users\Sercl\Desktop\todox\node_modules\@babel\core\lib\transformation\index.js:35:14)

@. / src/todo/todo.vue 8:0-14 9:0-12 7
@. / multi (webpack)-dev-server/client? http://0 < multi (webpack)-dev-server/client? http://0 < multi (webpack) > @. / src/app.vue
@. / src/index.js < loader > @. / nodecodes
@. / src/index.js < loader > @. / nodeparts
@. / src/index.js < loader > @ multi (webpack)-dev-server/client? http://0 .0.0.0 : 8080 webpack/hot/dev-server. / src/index.js
Child html-webpack-plugin for "index.html":

Vue-loader vue.js javascript

Jul.30,2021