Parse settings mutate defined objects as argument

[colbyfayock]

If I create a predefined object for the second argument, it would be mutated unexpectedly by the second time I invoke parse.

For instance:

const GEOJSON_PARSE_SETTINGS = {
  'Point': [
    'x',
    'y'
  ],
  'LineString': 'line',
  'Polygon': 'polygon'
};
return GeoJSON.parse(data, GEOJSON_PARSE_SETTINGS);

First time around it works, however the second time around, after being invoked, the object getting passed in there is actually:

{doThrows: {…}, geom: {…}} // GEOJSON_PARSE_SETTINGS output

This of course is avoidable by spreading it or cloning it, but just found it unexpected.