Function getOverlayableAxes

src/plots/cartesian/layout_defaults.js:169–182

(axLetter, axName)

    }

    function getOverlayableAxes(axLetter, axName) {
        var list = (axLetter === 'x') ? xNames : yNames;
        var out = [];

        for(var j = 0; j < list.length; j++) {
            var axName2 = list[j];

            if(axName2 !== axName && !(layoutIn[axName2] || {}).overlaying) {
                out.push(name2id(axName2));
            }
        }

        return out;
    }

    // list of available counter axis names
    var counterAxes = {x: getCounterAxes('x'), y: getCounterAxes('y')};