kotlin-stdlib / kotlin.collections / addAll addAll Common JVM JS Native 1.0 fun <T> MutableCollection<in T>.addAll( elements: Iterable<T>): Boolean(source) Adds all elements of the given elements collection to this MutableCollection. Common JVM JS Native 1.0 fun <T> MutableCollection<in T>.addAll( elements: Sequence<T>): Boolean(source) Adds all elements of the given elements sequence to this MutableCollection. Common JVM JS Native 1.0 fun <T> MutableCollection<in T>.addAll( elements: Array<out T>): Boolean(source) Adds all elements of the given elements array to this MutableCollection.