Effect Patterns Hub

Purpose: Provide quick access to 130+ curated Effect-TS patterns from the EffectPatterns repository. Use this skill to find specific implementation patterns, compare approaches, and reference best practices.

Triggers

Looking for a specific Effect pattern or idiom

Need real-world examples of Effect concepts

Want to see multiple approaches to the same problem

Comparing implementation strategies

Learning new Effect features

Pattern Library Location

Local Patterns

:

.claude/skills/effect-patterns-hub/patterns/

Documentation

:

docs/effect-patterns/

Count

130+ patterns in MDX format Quick Decision Tree I need to... Create Effects From value → constructor-succeed-some-right.mdx From sync code → constructor-sync-async.mdx From promise → constructor-try-trypromise.mdx From nullable → constructor-from-nullable-option-either.mdx Pre-resolved → create-pre-resolved-effect.mdx Transform & Compose Map values → combinator-map.mdx Chain effects → combinator-flatmap.mdx Sequence operations → combinator-sequencing.mdx Combine values → combinator-zip.mdx Filter → combinator-filter.mdx Conditional logic → combinator-conditional.mdx Process collections → combinator-foreach-all.mdx Control Flow Sequential logic → write-sequential-code-with-gen.mdx Business logic → use-gen-for-business-logic.mdx Pipe composition → use-pipe-for-composition.mdx Branching workflows → conditionally-branching-workflows.mdx Combinators → control-flow-with-combinators.mdx Repetition → control-repetition-with-schedule.mdx Error Handling Define errors → define-tagged-errors.mdx Catch specific errors → pattern-catchtag.mdx Handle all errors → handle-errors-with-catch.mdx Retry operations → retry-based-on-specific-errors.mdx Flaky operations → handle-flaky-operations-with-retry-timeout.mdx Map errors → mapping-errors-to-fit-your-domain.mdx Handle unexpected → handle-unexpected-errors-with-cause.mdx API errors → handle-api-errors.mdx Concurrency Parallel execution → run-effects-in-parallel-with-all.mdx Background tasks → run-background-tasks-with-fork.mdx Process collections → process-collection-in-parallel-with-foreach.mdx Race effects → race-concurrent-effects.mdx Fibers explained → understand-fibers-as-lightweight-threads.mdx Decouple with queues → decouple-fibers-with-queue-pubsub.mdx Polling → poll-for-status-until-task-completes.mdx Graceful shutdown → implement-graceful-shutdown.mdx Services & Dependency Injection Model dependencies → model-dependencies-as-services.mdx Understand layers → understand-layers-for-dependency-injection.mdx Scoped services → scoped-service-layer.mdx Composable modules → organize-layers-into-composable-modules.mdx Compose scoped layers → compose-scoped-layers.mdx Provide config → provide-config-layer.mdx Caching wrapper → add-caching-by-wrapping-a-layer.mdx Resource Management Bracket pattern → safely-bracket-resource-usage.mdx Scope management → manage-resource-lifecycles-with-scope.mdx Manual scope → manual-scope-management.mdx Scoped resources runtime → create-managed-runtime-for-scoped-resources.mdx Streaming Process streaming data → process-streaming-data-with-stream.mdx From iterable → stream-from-iterable.mdx From file → stream-from-file.mdx From paginated API → stream-from-paginated-api.mdx Concurrent processing → stream-process-concurrently.mdx Batch processing → stream-process-in-batches.mdx Collect results → stream-collect-results.mdx Run for effects → stream-run-for-effects.mdx Manage resources → stream-manage-resources.mdx Retry on failure → stream-retry-on-failure.mdx Schema & Validation Define contracts → define-contracts-with-schema.mdx Parse/decode → parse-with-schema-decode.mdx Transform data → transform-data-with-schema.mdx Validate body → validate-request-body.mdx Brand types → brand-model-domain-type.mdx Brand validation → brand-validate-parse.mdx Config schema → define-config-schema.mdx Data Types Option → data-option.mdx , model-optional-values-with-option.mdx Either → data-either.mdx , accumulate-multiple-errors-with-either.mdx Chunk → data-chunk.mdx , use-chunk-for-high-performance-collections.mdx Array → data-array.mdx HashSet → data-hashset.mdx Duration → data-duration.mdx , representing-time-spans-with-duration.mdx DateTime → data-datetime.mdx , beyond-the-date-type.mdx BigDecimal → data-bigdecimal.mdx Cause → data-cause.mdx Exit → data-exit.mdx Ref → data-ref.mdx , manage-shared-state-with-ref.mdx Redacted → data-redacted.mdx Case → data-case.mdx Class → data-class.mdx Struct → data-struct.mdx Tuple → data-tuple.mdx Pattern Matching Match API → pattern-match.mdx Effectful match → pattern-matcheffect.mdx Tag matching → pattern-matchtag.mdx Option/Either checks → pattern-option-either-checks.mdx HTTP & Web Basic HTTP server → build-a-basic-http-server.mdx Launch server → launch-http-server.mdx Handle GET → handle-get-request.mdx HTTP client request → make-http-client-request.mdx Testable HTTP client → create-a-testable-http-client-service.mdx JSON response → send-json-response.mdx Path parameters → extract-path-parameters.mdx Provide dependencies to routes → provide-dependencies-to-routes.mdx Testing Mocking dependencies → mocking-dependencies-in-tests.mdx Use Default layer → use-default-layer-for-tests.mdx Tests adapt to code → write-tests-that-adapt-to-application-code.mdx Observability Structured logging → leverage-structured-logging.mdx , observability-structured-logging.mdx Tracing spans → trace-operations-with-spans.mdx , observability-tracing-spans.mdx Custom metrics → add-custom-metrics.mdx , observability-custom-metrics.mdx OpenTelemetry → observability-opentelemetry.mdx Effect.fn instrumentation → observability-effect-fn.mdx Runtime & Execution runPromise → execute-with-runpromise.mdx runSync → execute-with-runsync.mdx runFork → execute-long-running-apps-with-runfork.mdx Reusable runtime → create-reusable-runtime-from-layers.mdx Configuration Access config → access-config-in-context.mdx Define schema → define-config-schema.mdx Provide layer → provide-config-layer.mdx Time & Scheduling Current time → accessing-current-time-with-clock.mdx Duration → representing-time-spans-with-duration.mdx DateTime → beyond-the-date-type.mdx Schedule repetition → control-repetition-with-schedule.mdx Project Setup New project → setup-new-project.mdx Editor LSP → supercharge-your-editor-with-the-effect-lsp.mdx AI agents MCP → teach-your-ai-agents-effect-with-the-mcp-server.mdx Advanced Concepts Structural equality → comparing-data-by-value-with-structural-equality.mdx Effect channels → understand-effect-channels.mdx Effects are lazy → effects-are-lazy.mdx Not found vs errors → distinguish-not-found-from-errors.mdx Promise problems → solve-promise-problems-with-effect.mdx Avoid long chains → avoid-long-andthen-chains.mdx Pattern Categories By Skill Level Beginner (Getting Started) Constructor patterns (succeed, fail, sync, async) Basic combinators (map, flatMap, tap) Simple error handling (catch, catchTag) Effect.gen basics runPromise/runSync Intermediate (Building Applications) Services and layers Schema validation HTTP servers and clients Resource management Concurrency basics (Effect.all, fork) Testing with mocks Advanced (Production Systems) Complex layer composition Custom runtimes Streaming pipelines Graceful shutdown OpenTelemetry integration Performance optimization (Chunk, Ref) By Use Case Domain Modeling Schema definitions Brand types Tagged errors Option/Either for optional/fallible values API Development HTTP server setup Route handling Request validation Error handling Response formatting Data Processing Stream processing Batch operations Parallel processing Resource-safe pipelines Application Architecture Service layer design Dependency injection Module composition Configuration management Testing Mock layers Test utilities Testable services Observability Structured logging Distributed tracing Custom metrics Performance monitoring Search Patterns By Keyword Use Grep to search patterns by keyword:

Find patterns about error handling

grep -l "error" patterns/*.mdx

Find patterns about concurrency

grep -l "concurrent|parallel|fiber" patterns/*.mdx

Find patterns about HTTP

grep -l "http|server|client" patterns/*.mdx

Find patterns about testing

grep

-l

"test|mock"

patterns/*.mdx

By Frontmatter Tags

All patterns include metadata:

title

Human-readable name

id

Unique identifier (filename without extension)

skillLevel

beginner, intermediate, advanced

useCase

domain-modeling, error-handling, concurrency, etc.

summary

Brief description

tags

Keywords for searching

related

Links to related patterns

Common Searches

"How do I create an Effect from..."

→ Search constructor patterns:

grep -l "constructor" patterns/*.mdx

→ Check

constructor-*.mdx

files

"How do I handle errors when..."

→ Search error handling:

grep -l "error|catch|retry" patterns/*.mdx

→ Check

handle-*.mdx

and

pattern-catchtag.mdx

"How do I run multiple things concurrently?"

→ Search concurrency:

grep -l "concurrent|parallel|all|fork" patterns/*.mdx

→ Check

run-effects-in-parallel-with-all.mdx

"How do I work with services?"

→ Search services:

grep -l "service|layer|dependency" patterns/*.mdx

→ Check

model-dependencies-as-services.mdx

,

understand-layers-for-dependency-injection.mdx

"How do I validate data?"

→ Search schema:

grep -l "schema|validate|parse" patterns/*.mdx

→ Check

define-contracts-with-schema.mdx

,

parse-with-schema-decode.mdx

Integration with Other Skills

Foundations → Patterns Hub

When you need concrete examples for foundation concepts, check patterns:

effect-foundations

teaches concepts → patterns show implementation

Architect → Patterns Hub

When designing systems, reference architectural patterns:

Layer composition →

organize-layers-into-composable-modules.mdx

Service design →

model-dependencies-as-services.mdx

Scoped resources →

scoped-service-layer.mdx

Engineer → Patterns Hub

When implementing features, find relevant patterns:

HTTP endpoints →

handle-get-request.mdx

,

validate-request-body.mdx

Error handling →

retry-based-on-specific-errors.mdx

Concurrency →

run-effects-in-parallel-with-all.mdx

Tester → Patterns Hub

When writing tests, reference testing patterns:

Mock services →

mocking-dependencies-in-tests.mdx

Test layers →

use-default-layer-for-tests.mdx

Testable design →

write-tests-that-adapt-to-application-code.mdx

Usage Workflow

Identify Need

"I need to [do something] with Effect"

Check Decision Tree

Find relevant section above

Read Pattern

Use

Read

tool on the pattern file

Adapt to Context

Apply pattern to your specific use case

Check Related

Follow

related

links in pattern frontmatter

Consult Agent

If unclear, use @effect-engineer or @effect-architect Anti-Pattern Detection If you find yourself: Using imperative loops → Check process-collection-in-parallel-with-foreach.mdx Mixing promises and Effects → Check constructor-try-trypromise.mdx , solve-promise-problems-with-effect.mdx Long andThen chains → Check avoid-long-andthen-chains.mdx , use-gen-for-business-logic.mdx Leaking requirements → Check model-dependencies-as-services.mdx Manual resource cleanup → Check safely-bracket-resource-usage.mdx Pattern File Structure Each pattern file follows this structure:

title: Human-readable title id: kebab-case-id skillLevel: beginner | intermediate | advanced useCase: primary-use-case summary: Brief description tags: - keyword1 - keyword2 related: - related-pattern-id-1 - related-pattern-id-2 author: Author name

Title

Guideline

What to do

Rationale

Why do it this way

Good Example

✅ Recommended approach

Bad Example

❌ What to avoid

Related Patterns

Links to related patterns Maintenance Patterns are synced from EffectPatterns repository . To update patterns: cd /tmp git clone --depth = 1 https://github.com/PaulJPhilp/EffectPatterns.git cp -r EffectPatterns/content/published/ /Users/pooks/Dev/crate/.claude/skills/effect-patterns-hub/patterns/ cp -r EffectPatterns/content/published/ /Users/pooks/Dev/crate/docs/effect-patterns/ Summary 130+ patterns covering all Effect-TS concepts Decision tree for quick pattern lookup Integration with existing skills and agents Searchable by keyword, use case, skill level Examples showing good and bad practices Related patterns for deeper exploration Use this skill as your go-to reference for "How do I... with Effect?"