kotlin-coroutines-expert

name	kotlin-coroutines-expert
description	ALWAYS use this when the request matches Kotlin Coroutines Expert: Expert patterns for Kotlin Coroutines and Flow, covering structured concurrency, error handling, and testing.

Kotlin Coroutines Expert

Selective Reading Rule

Start with:

• references/senior-master-standard.md
• references/usage-routing.md
• references/quality-checklist.md

Then load only the inherited docs, scripts, assets, or examples that match the user's actual task.

Overview

A guide to mastering asynchronous programming with Kotlin Coroutines. Covers advanced topics like structured concurrency, Flow transformations, exception handling, and testing strategies.

When to Use This Skill

• Use when implementing asynchronous operations in Kotlin.
• Use when designing reactive data streams with Flow.
• Use when debugging coroutine cancellations or exceptions.
• Use when writing unit tests for suspending functions or Flows.

Step-by-Step Guide

1. Structured Concurrency

Always launch coroutines within a defined CoroutineScope. Use coroutineScope or supervisorScope to group concurrent tasks.

suspend fun loadDashboardData(): DashboardData = coroutineScope {
    val userDeferred = async { userRepo.getUser() }
    val settingsDeferred = async { settingsRepo.getSettings() }
    
    DashboardData(
        user = userDeferred.await(),
        settings = settingsDeferred.await()
    )
}