Equiavlent js Map

I have a set variable activity that returns a json object and I need to perform JS Array.prototype.map  equiavlent in Data Pipeline.

Can you please help. I don't want to manually hardcode by array index inside a concat

const obj = {
	"value": {
		"colNames": [
			{
				"tbl_id": 2,
				"tbl_name": "fact_Activity",
				"src_colname": "col1",
				"sample_datetime": "2024-08-02T04:23:18Z",
				"last_run_at": "2024-08-02T00:23:40.071123Z"
			},
			{
				"tbl_id": 2,
				"tbl_name": "fact_Activity",
				"src_colname": "col2",
				"sample_datetime": "2024-08-02T04:23:18Z",
				"last_run_at": "2024-08-02T00:23:40.071123Z"
			},
			{
				"tbl_id": 2,
				"tbl_name": "fact_Activity",
				"src_colname": "col3",				
				"sample_datetime": "2024-08-02T04:23:18Z",
				"last_run_at": "2024-08-02T00:23:40.071123Z"
			}
		]
	}

const result = obj.value.colNames.map(a=>a.src_colname).join(",")
//'col1,col2,col3'
}

@join(activity('Script1').output.resultSets[0].rows,',')

// this joins all the key-value pairs