Detecting artboard size for batch export

Thank you! Is there an example of proper syntax anywhere so I know how to grab that width properly?

I'm admittedly a bit new to this scripting. I have the following script, however my function completely ignores all of my 'if else' conditions and just overwrites each artboard as a PNG at 150% scaling over and over with the same name.

var docRef = app.activeDocument;  
var destFolder = Folder.selectDialog();
var num_artboards = docRef.artboards.length;
var i = 0;

var ab = docRef.artboards[0];  
var abBounds = ab.artboardRect;// left, top, right, bottom  

var ableft = abBounds[0];
var abtop = abBounds[1];
var abright = abBounds[2];  
var abbottom = abBounds[3];  
var abwidth = abright - ableft; 
var abheight = abtop- abbottom; 

var scale100options = new ExportOptionsPNG24();  
var scale125options = new ExportOptionsPNG24(); 
var scale150options = new ExportOptionsPNG24(); 
var scale200options = new ExportOptionsPNG24(); 
var scale300options = new ExportOptionsPNG24();  
var optionsprompt = new ExportOptionsPNG24();  
var type = ExportType.PNG24;  

//** Scaling Options **//
// Scale 100 Options
scale100options.artBoardClipping = true;  
scale100options.matte = false;  
scale100options.horizontalScale = scale100options.verticalScale = 100;

// Scale 125 Options
scale125options.artBoardClipping = true;  
scale125options.matte = false;  
scale125options.horizontalScale = scale125options.verticalScale = 125;

// Scale 150 Options
scale150options.artBoardClipping = true;  
scale150options.matte = false;  
scale150options.horizontalScale = scale150options.verticalScale = 150;

// Scale 200 Options
scale200options.artBoardClipping = true;  
scale200options.matte = false;  
scale200options.horizontalScale = scale200options.verticalScale = 200;

// Scale 300 Options
scale300options.artBoardClipping = true;  
scale300options.matte = false;  
scale300options.horizontalScale = scale300options.verticalScale = 300;

// Loop //
for (var i = 0; i < num_artboards; i++ ) {  
    docRef.artboards.setActiveArtboardIndex(i);
    detectSizes ();
}

function detectSizes () {
    var destFile = new File(destFolder + "/" + docRef.name + docRef.artboards[i].name);    
    
    if ( abwidth = 320 ) {
        app.activeDocument.exportFile (destFile, type, scale150options );  
    }
    else if ( abwidth = 360 ) {
        app.activeDocument.exportFile (destFile, type, scale300options );  
    } 
    else if ( abwidth = 480 ) {
        app.activeDocument.exportFile (destFile, type, scale150options );  
    } 
    else if ( abwidth = 540 ) {
        app.activeDocument.exportFile (destFile, type, scale200options );  
    } 
    else if ( abwidth = 640 ) {
        app.activeDocument.exportFile (destFile, type, scale125options );  
    } 
    else if ( abwidth = 1366 ) {
        app.activeDocument.exportFile (destFile, type, scale100options );  
    } 
    else if ( abwidth = 2560 ) {
        app.activeDocument.exportFile (destFile, type, scale100options );  
    } 
    else {
        app.activeDocument.exportFile (destFile, type, scale100options );  
    }   
}