web-annotation-utils/lib

export function asArray(value) {
    if (Array.isArray(value))
        return value;
    if (value === undefined || value === null)
        return [];
    return [value];
}
export function asSingleValue(value) {
    if (value instanceof Array)
        return value[0];
    if (value === undefined || value === null)
        return undefined;
    return value;
}