Method add

packages/table/src/regions.ts:229–233

* Adds the region to the end of a cloned copy of the supplied region * array.

(regions: IRegion[], region: IRegion)

     * array.
     */
    public static add(regions: IRegion[], region: IRegion) {
        const copy = regions.slice();
        copy.push(region);
        return copy;
    }

    /**
     * Replaces the region at the end of a cloned copy of the supplied region