Function unionExtentFromNumber

src/util/model.ts:1225–1230

(extent: number[], val: number | NullUndefined)

 *  - `extent` should be initialized as `initExtentForUnion()`.
 */
export function unionExtentFromNumber(extent: number[], val: number | NullUndefined): void {
    if (isValidNumberForExtent(val)) {
        val < extent[0] && (extent[0] = val);
        val > extent[1] && (extent[1] = val);
    }
}

/**
 * NOTICE: