Question Re: How to separate callback function from MessageBox. in Technology Q&A

How to separate callback function from MessageBox.

Former Member — Thu, 27 Feb 2020 08:21:32 GMT

Hello,

I am trying to create a function to delete data after user press delete button on MessageBox of confirmation.

I know that it will work following code;

MessageBox.confirm(
 "Delete data?", {
 title: "Delete confirmation",
 onClose: function(oAction) {
   switch(oAction) {
     case "OK":
       /* do delete operation */
       break;
     default:
       break;
 }
);

But, I want to know how to separate the callback function from the code of MessageBox as below, becasue this application needs post-processes after deletion so that the code will be longer, I think it should not be included in the code of calling MessageBox.

~~~~~~~
MessageBox.show(
 "Delete data?", {
 title: "Delete confirmation",
 onClose: ".afterDeleteConfirmation"
);

~~~~~~

afterDeleteConfirmation: function(oAction) {
   switch(oAction) {
     case "OK":
       /* do delete operation */
       break;
     default:
       break;
 }

Re: How to separate callback function from MessageBox.

former_member540067 — Thu, 27 Feb 2020 08:56:58 GMT

You can create a separate function and call it from the callback. Use the reference of this but you need to assign it to another variable outside the messagebox function.

~~~~~~~

var that=this;
MessageBox.show(
 "Delete data?", {
 title: "Delete confirmation",
 onClose: function(oAction){
     that.afterDeleteConfirmation(oAction);
     }
);

~~~~~~

afterDeleteConfirmation: function(oAction) {
   switch(oAction) {
     case "OK":
       /* do delete operation */
       break;
     default:
       break;
 }

Regards

Anmol

Re: How to separate callback function from MessageBox.

BhargavaTanguturi — Thu, 27 Feb 2020 09:53:20 GMT

Use Promise for callbacks.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise

see below code

fnConfirmationMsg: function(sMessage, sConfirmation) {

  return new Promise((fnResolve, fnReject ) => {
        MessageBox.show( sMessage, {
             title: sConfirmation,
             onClose: fnResolve
             }
        );
  });
 };

deleteRecord: function(oData) {
  this.fnConfirmationMsg("Delete data?", "Delete confirmation").then((sAction)=>{
        switch(oAction) {
         case "OK":
            /* do delete operation */
           break;
        default:
           break;
      })
};

Re: How to separate callback function from MessageBox.

Joseph_BERTHE1 — Fri, 28 Feb 2020 06:21:43 GMT

Hello,

You can simplify it like this :

MessageBox.show(
 "Delete data?", {
 title: "Delete confirmation",
 onClose: this.afterDeleteConfirmation.bind(this)
);

Regards,

Joseph

Re: How to separate callback function from MessageBox.

Former Member — Tue, 03 Mar 2020 00:25:04 GMT

Thank you.

That's what I wanted. The progrram needs error handling for the delete operation too so that I have to make chain of Promise.

Your code can be used for it too.

Re: How to separate callback function from MessageBox.

Former Member — Tue, 03 Mar 2020 00:26:45 GMT

Your answer also works and I learnt how to call function by using "that". Thank you.