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Extracting values from JSON objects in JSONTemplater

  • January 16, 2026
  • 6 replies
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bruceharold
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I’m having trouble finding examples for JSONTemplater when working with a JSON array input attribute.

The incoming data looks like this:

{"layers": [
		{
			"defaultVisibility": true,
			"geometryType": "esriGeometryPolygon",
			"id": 1,
			"maxScale": 0,
			"minScale": 0,
			"name": "Parcels",
			"parentLayerId": -1,
			"subLayerIds": null,
			"type": "Feature Layer"
		}
	]}

I’m interested in extracting the first array member id value into an object like this:

{"layers": [{"id": 1}]}

I can almost get the data into what I want in two steps, first extracting the value with a query json["layers"][0]["id"] and then using the JSONTemplater to use the id value, but bizarrely the value 1 is cast to string “1” byt the templater, which is invalid for downstream work.

Anyone know how to make what I want in one step with JSONTemplater?  Thanks.

Best answer by debbiatsafe

Hello ​@bruceharold,

You can use the following template in the JSONTemplater given the incoming JSON data is stored in an attribute named input:

{
    "layers" : [
        {
            let $firstArrObj := fme:get-json-attribute("input")("layers")(1)
            return {"id": $firstArrObj("id")}
        }
    ],
    "exportContingentValues":true
}

This should produce the output you want using only the JSONTemplater.

6 replies

ebygomm
Influencer
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  • ebygommInfluencer
  • Influencer
  • January 16, 2026

I don’t know the answer to your first question but if you don’t want quotes in the json templater you can do something like this

xs:int(fme:get-attribute("id"))

 

cfvonner
Supporter
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  • cfvonnerSupporter
  • Supporter
  • January 16, 2026

​@bruceharold Can you share what you have in the JSONTemplater?

bruceharold
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  • bruceharoldSupporter
  • Author
  • Supporter
  • January 16, 2026

I don’t know the answer to your first question but if you don’t want quotes in the json templater you can do something like this

xs:int(fme:get-attribute("id"))

 

Thank you!  As the JSON I want is very simple I’m using JSONExtractor and ExpressionEvaluator to get what I need but it would be good to find the canonical way.

bruceharold
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  • bruceharoldSupporter
  • Author
  • Supporter
  • January 16, 2026

​@bruceharold Can you share what you have in the JSONTemplater?

I’ve temporarily abandoned a JSONTemplater but it was (after extracting the id value into it’s own attribute):

{
  "layers": [{"id": fme:get-attribute("layerId")}],
  "exportContingentValues":true
}

debbiatsafe
Safer
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  • debbiatsafeSafer
  • Safer
  • Best Answer
  • January 19, 2026

Hello ​@bruceharold,

You can use the following template in the JSONTemplater given the incoming JSON data is stored in an attribute named input:

{
    "layers" : [
        {
            let $firstArrObj := fme:get-json-attribute("input")("layers")(1)
            return {"id": $firstArrObj("id")}
        }
    ],
    "exportContingentValues":true
}

This should produce the output you want using only the JSONTemplater.

bruceharold
Supporter
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  • bruceharoldSupporter
  • Author
  • Supporter
  • January 20, 2026

Thanks Debbie, but if I had to guess I would say the number of people who could get there from the doc is vanishingly small! 😉This might be a good place for some AI assistance if enough XQuery material is out on the web.

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