lazy-modules.md

title
Lazy Modules and Background Loading

In this section we will see how to organize your modules with lazy loading approach.

Defining Lazy Modules [Experimental]

You can now declare lazy Koin module, to avoid trigger any pre allocation of resources and load them in background with Koin start.

• lazyModule - declare a Lazy Kotlin version of Koin Module
• Module.includes - allow to include lazy Modules

A good example is always better to understand:

// Some lazy modules
val m2 = lazyModule {
    singleOf(::ClassB)
}

// include m2 lazy module
val m1 = lazyModule {
    includes(m2)
    singleOf(::ClassA) { bind<IClassA>() }
}

:::info LazyModule won't trigger any resources until it has been loaded by the following API :::

Background loading with Kotlin coroutines [Experimental]

Once you have declared some lazy modules, you can load them in background from your Koin configuration and further more.

• KoinApplication.lazyModules - load lazy modules in background with coroutines, regarding platform default Dispatchers
• Koin.waitAllStartJobs - wait for start jobs to complete
• Koin.runOnKoinStarted - run block code after start completion

A good example is always better to understand:

startKoin {
    // load lazy Modules in background
    lazyModules(m1)
}

val koin = KoinPlatform.getKoin()

// wait for loading jobs to finish
koin.waitAllStartJobs()

// or run code after loading is done
koin.runOnKoinStarted { koin ->
    // run after background load complete
}

:::note The lazyModules function allow you to specify a dispatcher: lazyModules(modules, dispatcher = Dispatcher.IO) :::

:::info Default dispatcher for coroutines engine is Dispatchers.Default :::