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returnkotlin

Is it good practice to use run function instead of return in Kotlin?

Kotlin has an extension function run.

/**
 * Calls the specified function [block] and returns its result.
 */
@kotlin.internal.InlineOnly
public inline fun <R> run(block: () -> R): R = block()

And run function can be used instead of return.

// an example multi-line method using return
fun plus(a: Int, b: Int): Int {
  val sum = a + b
  return sum
}

// uses run instead of return
fun plus(a: Int, b: Int): Int = run {
  val sum = a + b
  sum
}

Which style is better?

Solution

  • For more complicated functions the first option will be more readable. For simple functions I would suggest taking a look at Single-expression function syntax.

    fun plus(a: Int, b: Int): Int = a + b