*%(basename)s:9: TypeError: Converting circular structure to JSON
    --> starting at object with constructor 'Object'
    --- property 'key' closes the circle
JSON.stringify(object);
     ^
TypeError: Converting circular structure to JSON
    --> starting at object with constructor 'Object'
    --- property 'key' closes the circle
    at JSON.stringify (<anonymous>)
    at *%(basename)s:9:6