Function cloneSourceShallow

_benchmarks/sample_echarts.js:19820–19830

* Clone source but excludes source data.

(source)

     */

    function cloneSourceShallow(source) {
      return new SourceImpl({
        data: source.data,
        sourceFormat: source.sourceFormat,
        seriesLayoutBy: source.seriesLayoutBy,
        dimensionsDefine: clone(source.dimensionsDefine),
        startIndex: source.startIndex,
        dimensionsDetectedCount: source.dimensionsDetectedCount,
        encodeDefine: makeEncodeDefine(source.encodeDefine)
      });
    }

    function makeEncodeDefine(encodeDefine) {
      // null means user not specify `series.encode`.