1th School Project : Software Engineering__20210427 ts export,import class not found

Status Quo

I am importing 'reportUser' class
from 'index.ts'
to 'community.ts'

community.ts

import { reportUser } from "./domainModels/index"

const reportComments = class extends reportUser{
    constructor(divClassName : string, targetClassName : string){
        // constructor(){
        super()
        if (this.inputError(divClassName)) throw 'Error'
        if (this.inputError(targetClassName)) throw 'Error'
        this.contentsDiv = document.querySelector(`.${divClassName}`)
        this.targetClassName = targetClassName        
        // super(commentId,className)
    }
    report(){
        return;
    }
    clickHandler(e:any):void{
        if(e.target.classList.contains(this.targetClassName))
            this.executeClickHandler()
    }
    connectClickHandler(className : string) : void {
        this.contentsDiv!.addEventListener('click',this.clickHandler)
    }
    executeClickHandler() : void {throw 'override'}
}

index.ts

export const reportUser = class {
    contentId : number = 0 ;
    targetClassName : string = '';
    contentsDiv : HTMLDivElement | null = new HTMLDivElement() ;
    constructor(){
    // constructor(contentId : number, className : string){
        // contentId : 댓글 혹은 게시글 id
        // this.contentsDiv = document.querySelector(`.${className}`)
    }
    inputError(className : string):boolean{return !document.querySelector(`.${className}`) ? true : false}
    report() : void {throw 'override' }
    sampleClickHandler(className : string, e : any ) : void {throw 'override'}
    connectClickHandler(className : string, e : any ) : void {throw 'override'}
    executeClickHandler() : void {throw 'override'}
}

Problem

after applying 'community.js' to html file
below error occurs

Solution 1_1

in 'community.js'

import { reportUser } from "./domainModels/index"

to

import { reportUser } from "./domainModels/index.js"

Solution 1_2

ts.config.json

That is,

you have to explicitly mention 'js' in the end

why ?

we are compiliting ts code into js

and the browser will import 'JS' files not 'TS' files
that is why we have to explicitly tell 'JS' without omitting it

link

https://www.youtube.com/watch?v=EpOPR03z4Vw