Creating a Kotlin/JavaScript library
We will create a simple Kotlin/JavaScript library.
- Using our favorite editor, we create a new file called library.kt:
package org.sample fun factorial(n: Int): Long = if (n == 0) 1 else n * factorial(n - 1) inline fun IntRange.forOdd(f: (Int) -> Unit) { this.forEach { if (it % 2 == 1) f(it) } }
- Compile the library using the JS compiler
$ kotlinc-js -output sample-library.js -meta-info library.kt
The-meta-info
option indicates that an additional JS file with binary meta-information about compiled kotlin code will be created.If you want to see all available options run$ kotlinc-js -help
After compilation we have two new files:sample-library.js sample-library.meta.js
- You can simply distribute two JS files,
sample-library.js
andsample-library.meta.js
. The former file contains translated JavaScript code, the latter file contains some meta-information about Kotlin code, which is needed by compiler.Alternatively, you can append the content ofsample-library.meta.js
to the end ofsample-library.js
and distribute only the resulting file.Also you can create an archive, which can be distributed as a library:$ jar cf sample-library.jar *.js
Using a Kotlin/JavaScript library.
Create binom.kt:
import org.sample.factorial
fun binom(m: Int, n: Int): Long =
if (m < n) factorial(n) / factorial(m) / factorial(n-m) else 1
fun odd_factorial(n: Int): Long {
var result: Long = 1L
(1..n).forOdd { result = result * it }
return result
}
Compile with library:
$ kotlinc-js -output binom.js -library-files sample-library.meta.js binom.kt
Both files
sample-library.js
and sample-library.meta.js
should be present in the latter case, because translated JavaScript file contains meta-information about inlining, which is needed by compiler.
If you have an archive
sample-library.jar
, which contains sample-library.js
and sample-library.meta.js
, you can use the following command$ kotlinc-js -output binom.js -library-files sample-library.jar binom.kt
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