Function concat

packages/db/src/query/builder/functions.ts:305–325

(
  ...args: Array<ExpressionLike | ToArrayWrapper<any>>
)

): ConcatToArrayWrapper<T>
export function concat(...args: Array<ExpressionLike>): BasicExpression<string>
export function concat(
  ...args: Array<ExpressionLike | ToArrayWrapper<any>>
): BasicExpression<string> | ConcatToArrayWrapper<any> {
  const toArrayArg = args.find(
    (arg): arg is ToArrayWrapper<any> => arg instanceof ToArrayWrapper,
  )

  if (toArrayArg) {
    if (args.length !== 1) {
      throw new Error(
        `concat(toArray(...)) currently supports only a single toArray(...) argument`,
      )
    }
    return new ConcatToArrayWrapper(toArrayArg.query)
  }

  return new Func(
    `concat`,
    args.map((arg) => toExpression(arg)),
  )
}

// Helper type for coalesce: extracts non-nullish value types from all args
type CoalesceArgTypes<T extends Array<ExpressionLike>> = {