Running the script a second time, ae crashes

[damomoyu]

I tried writing a script to quickly replace placeholders and it worked, but the second time I ran it, AE crashed

    var myComp = app.project.activeItem;

    var ml = myComp.selectedLayers[0];

    if (ml.source.frameRate === 0) {

        var ml_Source_FrameRate = 1;

    }else{

        var ml_Source_FrameRate = ml.source.frameRate;

    };

    function searchLayer(string) {

        var itemNum = app.project.numItems;

        for (searchLayerIndex = 1; searchLayerIndex <= itemNum; searchLayerIndex++) {

            if (app.project.item(searchLayerIndex).name === string) {

                if (app.project.item(searchLayerIndex).file.fsName ===  ml.source.file.fsName) {

                    return searchLayerIndex;

                }

            };

        }

        return false;

    }

    searchLayer(ml.source.name);

    var ml_source_name = ml.source.name;

    app.project.item(searchLayerIndex).replaceWithPlaceholder("__placeholder__", ml.source.width, ml.source.height, ml_Source_FrameRate, ml.source.duration);

    ml.source.name = ml_source_name;

}

How can I modify it so that it can run the second time without ae crashing?

[Mylenium]

You may need to add a check for the layer type. After the first replacement procedure AE may simply try to replace a placeholder with another. Also the last curly brace doesn't seem to belong anywhere, so maybe it's throwing up on that because it expects a function.

Mylenium

[damomoyu]

Sorry, I'm missing some operations.
After I ran it the first time it was successful, I tried ctrl+z to restore it, and when I ran it again, ae crashed
I have tried not to use ctrl+z, after the material is replaced with a placeholder, re-replace the placeholder with a new material, and then run on this material, ae crashes
Please ignore the last "}", this is my wrong operation

[damomoyu · Accepted solution]

Sorry I found the cause of the error in my unpublished code, now it's fixed...

[damomoyu]

I'm using the wrong test to determine if the asset is an external asset

if (myComp.selectedLayers[0].source.file.fsName = null) {}
->
if (myComp.selectedLayers[0].source.file.fsName instanceof String) {}