Function normalizeToArray

src/util/model.ts:87–93

(value?: T | T[])

 * @return {Array} [value] or value
 */
export function normalizeToArray<T>(value?: T | T[]): T[] {
    return value instanceof Array
        ? value
        : value == null
        ? []
        : [value];
}

/**
 * Sync default option between normal and emphasis like `position` and `show`