How to check for presence of 'key' in jq before iterating over the values

Question

I get Cannot iterate over null (null) from the below query because .property_history is not present in result object.

How do i check for the presence of .property_history key before proceeding with map(...) ?

I tried using something like sold_year= `echo "$content" | jq 'if has("property_history") then map(select(.event_name == "Sold"))[0].date' else null end

Original Query:

sold_year=`echo "$content" | jq '.result.property_history | map(select(.event_name == "Sold"))[0].date'` 

JSON:

{      "result":{         "property_history":[            {               "date":"01/27/2016",             "price_changed":0,             "price":899750,             "event_name":"Listed",             "sqft":0          },          {               "date":"12/15/2015",             "price_changed":0,             "price":899750,             "event_name":"Listed",             "sqft":2357          },          {               "date":"08/30/2004",             "price_changed":0,             "price":739000,             "event_name":"Sold",             "sqft":2357          }       ]    } } 

Answer 1

You can use the select-expression in jq to do what you intend to achieve, something as,

jq '.result    | select(.property_history != null)    | .property_history    | map(select(.event_name == "Sold"))[0].date'