Function ReadonlyMap

packages/effect-app/src/Schema/ext.ts:369–393

(pair: {
  readonly key: KeySchema
  readonly value: ValueSchema
})

         * data:** a missing field may be data corruption, not an old-shape
         * document; silently substituting an empty map hides the problem.
         * Prefer an explicit, preferably versioned migration over a
         * decode-time fallback. See file-level note.
         */
        withDecodingDefaultType: s.pipe(S.withDecodingDefaultType(Effect.sync(() => new Map())))
      })
  )

/** Like the default Schema `NullOr` but with default helpers. */
export const NullOr = <Schema extends S.Top>(self: Schema) =>
  pipe(
    S.NullOr(self),
    (s) =>
      Object.assign(s, {
        /**
         * Construction-only default `null`. Applied only when the field is
         * omitted from `.make(...)` input. NOT applied during decode —
         * cannot be used to JIT-migrate database fields. See file-level
         * note.
         */
        withConstructorDefault: s.pipe(S.withConstructorDefault(Effect.succeed(null))),
        /**
         * Decode-time default `null`. **Discouraged for persisted data:** a
         * missing field may be data corruption, not an old-shape document;
         * silently substituting `null` hides the problem. Prefer an
         * explicit, preferably versioned migration over a decode-time
         * fallback. See file-level note.
         */
        withDecodingDefaultType: s.pipe(S.withDecodingDefaultType(Effect.succeed(null)))