how to get the placed layer details

As for the name: 

// based on code by michael l hale;
// 2024, use it at your own risk;
#target photoshop
if (app.documents.length > 0) {
var ref = new ActionReference();
ref.putEnumerated( charIDToTypeID("Lyr "), charIDToTypeID("Ordn"), charIDToTypeID("Trgt") ); 
var layerDesc = executeActionGet(ref);
var soDesc = layerDesc.getObjectValue(stringIDToTypeID('smartObject'));
alert (soDesc.getString(stringIDToTypeID('fileReference')));
};

»here in the above screenshot first layer contains the placed layer , when i double click one png file will open.
so how get that png file details, like width,height,name and image data.«

What do you mean by »image data«? 

// based on code by michael l hale;
// 2024, use it at your own risk;
#target photoshop
if (app.documents.length > 0) {
var ref = new ActionReference();
ref.putEnumerated( charIDToTypeID("Lyr "), charIDToTypeID("Ordn"), charIDToTypeID("Trgt") ); 
var layerDesc = executeActionGet(ref);
var soDesc = layerDesc.getObjectValue(stringIDToTypeID('smartObject'));
var soMoreDesc = layerDesc.getObjectValue(stringIDToTypeID('smartObjectMore'));
checkDesc2 (soMoreDesc.getObjectValue(stringIDToTypeID("size")));
};
////// based on code by michael l hale //////
function checkDesc2 (theDesc) {
var c = theDesc.count;
var str = '';
for(var i=0;i<c;i++){ //enumerate descriptor's keys
	str = str + 'Key '+i+' = '+typeIDToStringID(theDesc.getKey(i))+': '+theDesc.getType(theDesc.getKey(i))+'\n'+getValues (theDesc, i)+'\n';
	};
alert("desc\n\n"+str);
};
////// check //////
function getValues (theDesc, theNumber) {
switch (theDesc.getType(theDesc.getKey(theNumber))) {
case DescValueType.ALIASTYPE:
return theDesc.getPath(theDesc.getKey(theNumber));
break;
case DescValueType.BOOLEANTYPE:
return theDesc.getBoolean(theDesc.getKey(theNumber));
break;
case DescValueType.CLASSTYPE:
return theDesc.getClass(theDesc.getKey(theNumber));
break;
case DescValueType.DOUBLETYPE:
return theDesc.getDouble(theDesc.getKey(theNumber));
break;
case DescValueType.ENUMERATEDTYPE:
return (typeIDToStringID(theDesc.getEnumerationValue(theDesc.getKey(theNumber)))+"_"+typeIDToStringID(theDesc.getEnumerationType(theDesc.getKey(theNumber))));
break;
case DescValueType.INTEGERTYPE:
return theDesc.getInteger(theDesc.getKey(theNumber));
break;
case DescValueType.LISTTYPE:
return theDesc.getList(theDesc.getKey(theNumber));
break;
case DescValueType.OBJECTTYPE:
return (theDesc.getObjectValue(theDesc.getKey(theNumber))+"_"+typeIDToStringID(theDesc.getObjectType(theDesc.getKey(theNumber))));
break;
case DescValueType.REFERENCETYPE:
return theDesc.getReference(theDesc.getKey(theNumber));
break;
case DescValueType.STRINGTYPE:
return theDesc.getString(theDesc.getKey(theNumber));
break;
case DescValueType.UNITDOUBLE:
return (theDesc.getUnitDoubleValue(theDesc.getKey(theNumber))+"_"+typeIDToStringID(theDesc.getUnitDoubleType(theDesc.getKey(theNumber))));
break;
default: 
break;
};
};

Document properties code example:

https://github.com/MarshySwamp/Photoshop-Document-Dimensions---MP-Value---Aspect-Ratio/blob/main/Photoshop%20Document%20Dimensions%20-%20MP%20Value%20-%20Aspect%20Ratio.jsx

Layer properties code example:

https://gist.github.com/MarshySwamp/ef345ef3dec60a843465347ee6fcae2f

@Mahesh12 

To edit/open a Photoshop-compatible raster Smart Object layer/file (assumed as placed or embedded):

if (app.activeDocument.activeLayer.kind == LayerKind.SMARTOBJECT) {
    app.runMenuItem(stringIDToTypeID('placedLayerEditContents'));
}

You can then use the document class properties:

https://theiviaxx.github.io/photoshop-docs/Photoshop/Document.html

alert("Doc width: " + app.activeDocument.width);

// or

alert("Doc width: " + app.activeDocument.width.value);

// or

var savedRuler = app.preferences.rulerUnits;
app.preferences.rulerUnits = Units.PIXELS;
alert("Doc height: " + app.activeDocument.height.value);
app.preferences.rulerUnits = savedRuler;

// or

alert("Doc height: " + app.activeDocument.height.as('px'));

I believe that the code from @c.pfaffenbichler directly retrieved the properties of the SO without opening it.

Continued from this post:

https://community.adobe.com/t5/photoshop-ecosystem-discussions/how-to-get-the-smart-object-details/m-p/14781551