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Mechanical migration of every TypeScript example (content/**/*.mdx)
from Effect v3 to Effect v4, following the official v3-to-v4 migration
guides (Effect-TS/effect MIGRATION.md + migration/*).
Highlights:
- Services: Context.GenericTag/Tag, Effect.Tag/Service -> Context.Service
with make + explicit static layer; .Default -> .layer
- Errors: catchAll -> catch, catchAllCause -> catchCause,
catchAllDefect -> catchDefect, catchSome -> catchFilter
- Either -> Result (succeed/fail, isSuccess/isFailure, getSuccess/
getFailure, mapError, fromNullishOr, match onFailure/onSuccess,
_tag Success/Failure); Effect.either -> Effect.result
- Concurrency: Effect.fork -> forkChild, forkDaemon -> forkDetach
- Constructors: Effect.async -> Effect.callback; Scope.extend -> Scope.provide
- Schema: decode/encode -> decodeEffect/encodeEffect (+Unknown variants),
Either decoders -> Exit/Result variants, Literal/Union/Tuple ->
array form, Record({k,v}) shape, Transform -> decodeTo +
SchemaTransformation.transform, Struct spread/Struct.pick/omit/map
instead of extend/pick/omit/partial, filters -> check(is*),
filter() -> check(makeFilter()), Date -> DateFromString (Date kept
for Date-typed targets), TaggedError/Data APIs kept where valid
- Time: DurationInput -> Input, decode -> fromInputUnsafe,
lessThanOrEqualTo/greaterThan -> is* predicates
- Schedule: intersect/union/compose -> max/min, tap/while/delayed/
until/recurWhile/filter/upTo/jittered moved to v4 signatures,
Command -> ChildProcess + ChildProcessSpawner, Stream.fromChunk ->
fromArray, Http.* namespace -> HttpRouter/HttpServerRequest/
HttpServerResponse from effect/http, platform HttpClient.* ->
effect/http, FileSystem/Terminal stay in effect barrel,
KeyValueStore -> effect/persistence
- Deps: effect + @effect/* bumped to 4.0.0-rc.117; folded packages
(@effect/platform, @effect/schema, @effect/rpc, @effect/cli)
removed (now part of effect core)
Notes / follow-ups:
- import paths use final v4 layout (effect/http, effect/process,
effect/sql, ...) per MIGRATION.md; the npm rc.117 build still
exposes them under effect/unstable/*, main branch already uses
the final paths
- packages/*/src application code is NOT migrated yet (blocked on
@effect/cli v4); run bun install to refresh the lockfile
- Data.TaggedError kept intentionally (still valid v4)
…Is, add missing v4 courses - Remove 5 Schema.filterEffect courses (API removed in v4, no drop-in): schema/async-validation/basic-async, batched-async, database-checks, external-api-validation, schema/form-validation/async-validation - Add schema/async-validation/async-validation-with-effects (decode + Effect, transformEffect inline alternative, verified vs 4.0.0-rc.117) - Fix Schema.optionalWith -> withDecodingDefaultKey in 6 files (optional-fields, with-defaults, multiple-files, database-columns, postgres-jsonb, schema-evolution) - Fix Cause.failures/defects -> reasons filter in error-management-extract-cause; FiberRef/Effect.runtime -> References/Effect.context in tooling-devtools - Fix schema-vs-zod filterEffect placeholder -> transformEffect - Update Result prose Left/Right -> Success/Failure (3 files) - Add missing v4 courses: Context.Reference, Effect.fn, context-not-runtime, cause reasons array, Scope.provide Verified with bun vs effect@4.0.0-rc.117. Yieldable/.asEffect intentionally omitted: documented but not functional in rc.117.
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Summary
Migrates every TypeScript example under
content/(211 published pattern files + roadmap + drafts, ~600 code blocks) from Effect v3 to Effect v4 syntax, following the official v3→v4 migration guides (MIGRATION.md+migration/*in Effect-TS/effect).Branch:
valkalon:effect-v4-migration(256 files, +2269/−2309).What changed (examples only)
Context.GenericTag/Tag,Effect.Tag/Service→Context.Servicewithmake+ explicitstatic layer;.Default→.layercatchAll→catch,catchAllCause→catchCause,catchAllDefect→catchDefectmatchhandlers,_tagchecks,Effect.either→Effect.resultEffect.fork→forkChild,forkDaemon→forkDetachEffect.async→Effect.callback,Scope.extend→Scope.provide,fromNullable/fromEither→fromNullishOr/fromResultdecode/encode→decodeEffect/encodeEffectfamily, variadicLiteral/Union/Tuple→ array form,Record({k,v\}),transform→decodeTo+SchemaTransformation.transform, struct spread /Struct.pick/omit/mapinstead ofextend/pick/omit/partial, filters →check(is*),filter()→check(makeFilter()),Date→DateFromString(kept for Date-typed targets)DurationInput→Input,decode→fromInputUnsafe, comparison predicates gainisprefixintersect/union/compose→max/min,tap*/while*/until*/recurWhile/delayed/filter/upTo/jitteredmoved to v4 signaturesCommand→ChildProcess+ChildProcessSpawner,Stream.fromChunk→fromArray,Http.*namespace →HttpRouter/HttpServerRequest/HttpServerResponsefromeffect/http,NodeContext→NodeServices,NodeHttpServer.layertakes the server factory,HttpClientResponse.json(x)→x.jsonData.struct/array/tuple/caselessons rewritten for v4 structural equality on plain valueseffect+@effect/*bumped to4.0.0-rc.117; folded packages (@effect/platform,@effect/schema,@effect/rpc,@effect/cli) removedVerification
effect@4.0.0-rc.117+@effect/platform-node@4.0.0-rc.117Notes / follow-ups (not in scope)
effect/http,effect/process, …) perMIGRATION.md; the npm rc.117 build still exposes them undereffect/unstable/*(main branch already uses final paths) — a one-linesedflips back if you want to pin the rc exactlypackages/*/srcapplication code is not migrated (blocked on@effect/cliv4);bun installneeded to refresh the lockfileData.TaggedErrorkept intentionally (still valid v4)