Function applyDataTransform

src/data/helper/transform.ts:363–390

(
    rawTransOption: DataTransformOption | PipedDataTransformOption,
    sourceList: Source[],
    infoForPrint: { datasetIndex: number }
)

}

export function applyDataTransform(
    rawTransOption: DataTransformOption | PipedDataTransformOption,
    sourceList: Source[],
    infoForPrint: { datasetIndex: number }
): Source[] {
    const pipedTransOption: PipedDataTransformOption = normalizeToArray(rawTransOption);
    const pipeLen = pipedTransOption.length;

    let errMsg = '';
    if (!pipeLen) {
        if (__DEV__) {
            errMsg = 'If `transform` declared, it should at least contain one transform.';
        }
        throwError(errMsg);
    }

    for (let i = 0, len = pipeLen; i < len; i++) {
        const transOption = pipedTransOption[i];
        sourceList = applySingleDataTransform(transOption, sourceList, infoForPrint, pipeLen === 1 ? null : i);
        // piped transform only support single input, except the fist one.
        // piped transform only support single output, except the last one.
        if (i !== len - 1) {
            sourceList.length = Math.max(sourceList.length, 1);
        }
    }

    return sourceList;
}

function applySingleDataTransform(
    transOption: DataTransformOption,