function retrieveRawOption(option) {
    var ret = {};
    each$19(
        ['start', 'end', 'startValue', 'endValue', 'throttle'],
        function (name) {
            option.hasOwnProperty(name) && (ret[name] = option[name]);
        }
    );
    return ret;
}
Find the first target coordinate system.

@protected
@return {Object} {
                  grid: [
                      {model: coord0, axisModels: [axis1, axis3], coordIndex: 1},
                      {model: coord1, axisModels: [axis0, axis2], coordIndex: 0},
                      ...
                  ],  // cartesians must not be null/undefined.
                  polar: [
                      {model: coord0, axisModels: [axis4], coordIndex: 0},
                      ...
                  ],  // polars must not be null/undefined.
                  singleAxis: [
                      {model: coord0, axisModels: [], coordIndex: 0}
                  ]