Incorrect Minification of unused variable

[IrvinDominin]

Describe the bug
The minified code have a bug and breaks when executed; because the variable t not exists. Currenlty I have fixed the code by removing the unused variable.

To Reproduce
You can use the attached Program.cs the code to minify is there.

Minified output or stack trace
var actions={GOSUB:{action:function(){var t,n;if(vidData.inputGrids.length!=0&&options[BC_const.CUSTOM_PROP.ValidaDati]==BC_const.VALIDA_DATI.Oggetto){t={};let t;$(vidData.inputGrids).each(function(){var n=this,i=$("#"+n+"_grid",$videata);let r=$videata.find("#"+n);i[0].ej2_instances[0].isEdit&&(t=i)});t?(n=function(){let n=new $.Deferred;return options.actionId?(t.Wrapper().addDOMMethod(BC_const.EVENTS.GridRowSaved,function(t){t?n.resolve():n.reject()}),t.Wrapper().callDOMMethod(BC_const.EVENTS.GridOutRiga)):n.resolve(),n.promise()},n().then(function(){options.AMBITO&&options.AMBITO.TIPO===BC_const.RIBBONBAR_BUTTON_AMBITO_TIPO.GrigliaNuovaRiga&&t.Wrapper().callDOMMethod(BC_const.EVENTS.GridNewRowPage);$(container).Sistemi().goSub(options)})):$(container).Sistemi().goSub(options)}else $(container).Sistemi().goSub(options)}}}

Excepted output code
var actions={GOSUB:{action:function(){if(vidData.inputGrids.length!=0&&options[BC_const.CUSTOM_PROP.ValidaDati]==BC_const.VALIDA_DATI.Oggetto){var n={};let t;$(vidData.inputGrids).each(function(){var n=this,i=$("#"+n+"_grid",$videata);let r=$videata.find("#"+n);i[0].ej2_instances[0].isEdit&&(t=i)});t?(n=function(){let n=new $.Deferred;return options.actionId?(t.Wrapper().addDOMMethod(BC_const.EVENTS.GridRowSaved,function(t){t?n.resolve():n.reject()}),t.Wrapper().callDOMMethod(BC_const.EVENTS.GridOutRiga)):n.resolve(),n.promise()},n().then(function(){options.AMBITO&&options.AMBITO.TIPO===BC_const.RIBBONBAR_BUTTON_AMBITO_TIPO.GrigliaNuovaRiga&&t.Wrapper().callDOMMethod(BC_const.EVENTS.GridNewRowPage);$(container).Sistemi().goSub(options)})):$(container).Sistemi().goSub(options)}else $(container).Sistemi().goSub(options)}}}

Program.zip

[trullock]

Can you simplify the repro please

[IrvinDominin]

Hi @trullock thank you, i simplified it to:

            var script = @"var actions = {
                'GOSUB': {
                    action: function () {

                        if (vidData.inputGrids.length != 0 && options[BC_const.CUSTOM_PROP.ValidaDati] == BC_const.VALIDA_DATI.Oggetto) {
                            // se ci sono griglie di input, per le azioni con CONVARIABILI occorre effettuare validazione
                            var inputGrids = {};
                            let $editGrid;

                            if ($editGrid) {
                                var gosubAction = function () {
                                    let deferred = new $.Deferred();

                                    if (options['actionId']) {
                                    }
                                    else
                                        deferred.resolve();

                                    return deferred.promise();
                                }
                            }
                        }
                    }
                }";

[trullock]

Thanks, im certain you can get it simpler though. Every extra statement will make debugging much harder

[IrvinDominin]

Hi @trullock , thank you, I simplified it to a minimal reprex:

var script = @"var actions = function () {
    let $editGrid;
    var gosubAction = function () {
        let deferred = new Deferred();
    }
}";

[jzabroski]

Variation (reduced from fontawesome 6.7.2):

(function () {
  'use strict';

  let _DOCUMENT = {};
  const DOCUMENT = _DOCUMENT;
  const IS_DOM = !!DOCUMENT.documentElement && !!DOCUMENT.head && typeof DOCUMENT.addEventListener === 'function' && typeof DOCUMENT.createElement === 'function';
  function insertCss(css) {
    if (!css || !IS_DOM) {
      return;
    }
    return css;
  }
})()

[trullock]

its a bug with let, workaround is to use var