Function extend

packages/utils/src/index.ts:326–371

(
  original: Record<string, any>,
  additional: Record<string, any> | string | null,
  extendArrays = false,
  ignoreUndefined = false
)

 *
 */
export const extend = /*#__NO_SIDE_EFFECTS__*/ (
  original: Record<string, any>,
  additional: Record<string, any> | string | null,
  extendArrays = false,
  ignoreUndefined = false
): Record<string, any> | string | null => {
  if (additional === null) return null
  const merged: Record<string, any> = {}
  if (typeof additional === 'string') return additional
  for (const key in original) {
    if (
      has(additional, key) &&
      (additional[key] !== undefined || !ignoreUndefined)
    ) {
      if (
        extendArrays &&
        Array.isArray(original[key]) &&
        Array.isArray(additional[key])
      ) {
        merged[key] = original[key].concat(additional[key])
        continue
      }
      if (additional[key] === undefined) {
        continue
      }
      if (isPojo(original[key]) && isPojo(additional[key])) {
        merged[key] = extend(
          original[key],
          additional[key],
          extendArrays,
          ignoreUndefined
        )
      } else {
        merged[key] = additional[key]
      }
    } else {
      merged[key] = original[key]
    }
  }
  for (const key in additional) {
    if (!has(merged, key) && additional[key] !== undefined) {
      merged[key] = additional[key]
    }
  }
  return merged
}

/**
 * Determine if the given string is fully quoted.