Function determineSourceDimensions

src/data/Source.ts:300–401

* Determine the source definitions from data standalone dimensions definitions * are not specified.

(
    data: OptionSourceData,
    sourceFormat: SourceFormat,
    seriesLayoutBy: SeriesLayoutBy,
    sourceHeader: OptionSourceHeader,
    // standalone raw dimensions definition, like:
    // {
    //     dimensions: ['aa', 'bb', { name: 'cc', type: 'time' }]
    // }
    // in `dataset` or `series`
    dimensionsDefine: DimensionDefinitionLoose[]
)

 * are not specified.
 */
function determineSourceDimensions(
    data: OptionSourceData,
    sourceFormat: SourceFormat,
    seriesLayoutBy: SeriesLayoutBy,
    sourceHeader: OptionSourceHeader,
    // standalone raw dimensions definition, like:
    // {
    //     dimensions: ['aa', 'bb', { name: 'cc', type: 'time' }]
    // }
    // in `dataset` or `series`
    dimensionsDefine: DimensionDefinitionLoose[]
): {
    // If the input `dimensionsDefine` is specified, return it.
    // Else determine dimensions from the input `data`.
    // If not determined, `dimensionsDefine` will be null/undefined.
    dimensionsDefine: Source['dimensionsDefine'];
    startIndex: Source['startIndex'];
    dimensionsDetectedCount: Source['dimensionsDetectedCount'];
} {
    let dimensionsDetectedCount;
    let startIndex: number;

    // PENDING: Could data be null/undefined here?
    // currently, if `dataset.source` not specified, error thrown.
    // if `series.data` not specified, nothing rendered without error thrown.
    // Should test these cases.
    if (!data) {
        return {
            dimensionsDefine: normalizeDimensionsOption(dimensionsDefine),
            startIndex,
            dimensionsDetectedCount
        };
    }

    if (sourceFormat === SOURCE_FORMAT_ARRAY_ROWS) {
        const dataArrayRows = data as OptionSourceDataArrayRows;
        // Rule: Most of the first line are string: it is header.
        // Caution: consider a line with 5 string and 1 number,
        // it still can not be sure it is a head, because the
        // 5 string may be 5 values of category columns.
        if (sourceHeader === 'auto' || sourceHeader == null) {
            arrayRowsTravelFirst(function (val) {
                // '-' is regarded as null/undefined.
                if (val != null && val !== '-') {
                    if (isString(val)) {
                        startIndex == null && (startIndex = 1);
                    }
                    else {
                        startIndex = 0;
                    }
                }
            // 10 is an experience number, avoid long loop.
            }, seriesLayoutBy, dataArrayRows, 10);
        }
        else {
            startIndex = isNumber(sourceHeader) ? sourceHeader : sourceHeader ? 1 : 0;
        }