Call typescript function on button onclick event in SPFx(No Javascript Framework)

Try the code below: (Not a good practice to repeat loops but it was the only thing working for me)

private _renderListCustomer(items:ISPListCustomerItem[]):void{ let html:string=`<table width='100%' border=1 id="tblEmployees" class="table">`; html+=`<thead> <th scope="col">Customer Id</th> <th scope="col">Name</th> <th scope="col">Address</th> <th scope="col">Type</th> <th scope="col">Update</th> </thead><tbody>`; debugger; type NewType = ISPListCustomerItem; items.forEach((item:NewType)=> { html+= `<tr> <td>${item.CustomerID}</td> <td>${item.CustomerName}</td> <td>${item.CustomerAddress}</td> <td>${item.CustomerType}</td> <td><button id="btn${item.ID}" item-id="${item.ID}" type="submit" class="update btn btn-primary" data-toggle="modal" data-target="#DivUpdateItem">Update</button></td> </tr>`; }); html+=`</tbody></table>`; const listContainer:Element=this.domElement.querySelector("#spListContainer"); listContainer.innerHTML=html; this._setButtonEventHandlers(items); } //Method to called // Id:number public BindItem(id:number):void{ pnp.sp.web.lists.getByTitle("Customers").items.getById(id).select("*,CustType/Id,CustType/CType").expand("CustType").get(). then((item:ISPListCustomerItem)=>{console.log(item); document.getElementById('txtTitleUpdate')["value"]=item.Title , document.getElementById('txtCustomerIDUpdate')["value"]=item.CustomerID, document.getElementById('txtCustomerAddressUpdate')["value"]=item.CustomerAddress, document.getElementById('txtCustomerNameUpdate')["value"]=item.CustomerName, document.getElementById('txtCustomerTypeUpdate')["value"]=item.CustomerType, document.getElementById('ddlCustTypeUpdate')["value"]=item.CustType.ID}). catch((error)=>{ alert(error); error; }) } //function to bind on click event private _setButtonEventHandlers(items): void { const webPart: SpfxNoJswpWebPart = this; //replace SpfxNoJswpWebPart with your webpart class name items.forEach((item)=>{ this.domElement.querySelector('#btn'+item).addEventListener('click', () => { this.BindItem(item.ID); }); }); }