Functional fashion for Kotlin projects
summary
Builds an end-to-end Ktor + Arrow.kt end-to-end example that actually wires request → DB → response using suspend lambdas, extension functions and immutable domain types. Shows composing a circuit breakers and schedulers workflow for retries (decorator-style billing + breaker) and a resource-based lifecycle that cleanly shuts down. Demonstrates validation that accumulates validation with traverse across order entries (parallel traversal, fail-fast with bind) and replaces exceptions with typed error data so the pipeline compiles and runs.
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chapters (17)
- 0:00Introduction
- 3:22Functional style in Kotlin
- 7:34Functional fashion principles
- 12:12Explicit domain types
- 17:59Controlling effects
- 18:20Refactor Java to Kotlin
- 24:03Kotlin lambdas with suspend
- 24:26Ktor framework intro
- 31:13Ktor plugins and DB
- 32:15Arrow KT overview
- 34:23Domain modeling with Arrow
- 36:51Extension functions
- 39:18Arrow validation
- 41:46Arrow Either and bind
- 47:49Fail-fast strategy
- 48:30Resource management
- 50:15Further learning
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