Method _updateDims

src/data/DataStore.ts:811–863

(
        target: DataStore,
        dims: DimensionIndex[],
        cb: MapCb
    )

    }

    private _updateDims(
        target: DataStore,
        dims: DimensionIndex[],
        cb: MapCb
    ) {
        const targetChunks = target._chunks;

        const tmpRetValue = [];
        const dimSize = dims.length;
        const dataCount = target.count();
        const values = [];
        const rawExtent = target._rawExtent;

        for (let i = 0; i < dims.length; i++) {
            rawExtent[dims[i]] = initExtentForUnion();
        }

        for (let dataIndex = 0; dataIndex < dataCount; dataIndex++) {
            const rawIndex = target.getRawIndex(dataIndex);

            for (let k = 0; k < dimSize; k++) {
                values[k] = targetChunks[dims[k]][rawIndex];
            }
            values[dimSize] = dataIndex;

            let retValue = cb && cb.apply(null, values);
            if (retValue != null) {
                // a number or string (in ordinal dimension)?
                if (typeof retValue !== 'object') {
                    tmpRetValue[0] = retValue;
                    retValue = tmpRetValue;
                }

                for (let i = 0; i < retValue.length; i++) {
                    const dim = dims[i];
                    const val = retValue[i];
                    const rawExtentOnDim = rawExtent[dim];

                    const dimStore = targetChunks[dim];
                    if (dimStore) {
                        (dimStore as ParsedValue[])[rawIndex] = val;
                    }

                    if (val < rawExtentOnDim[0]) {
                        rawExtentOnDim[0] = val as number;
                    }
                    if (val > rawExtentOnDim[1]) {
                        rawExtentOnDim[1] = val as number;
                    }
                }
            }
        }
    }

    /**
     * Large data down sampling using largest-triangle-three-buckets