SkipScript provides a unified interface to the JavaScriptCore script engine on both iOS (using the platform-provided JavaScriptCore libraries) and on Android (using the bundled libjsc.so library). SkipScript enables a single scripting language (JavaScript) to be embedded in a dual-platform Skip app and provide the exact same behavior on both platforms.

To include this framework in your project, add the following dependency to your Package.swift file:

let package = Package(
    name: "my-package",
    products: [
        .library(name: "MyProduct", targets: ["MyTarget"]),
    ],
    dependencies: [
        .package(url: "https://source.skip.dev/skip-script.git", from: "1.0.0"),
    ],
    targets: [
        .target(name: "MyTarget", dependencies: [
            .product(name: "SkipScript", package: "skip-script")
        ])
    ]
)

as a dependency and a Swift source file imports the JavaScriptCore framework.

In this case, a subset of the the Objective-C JavaScriptAPI is mimicked on the Kotlin side, passing the calls through to the underlying C interface to the JavaScriptCore API using JNA and SkipFFI.

An example of evaluating some JavaScript:

import SkipScript

let ctx = try JSContext()
let num = ctx.evaluateScript("1 + 2.3")
assert(num.toDouble() == 3.3)

NOTE: JIT compilation is blocked on iOS without a special entitlement, which can drastically impact the performance of JavaScriptCore on iOS compared to either macOS or Android (where JIT is not blocked).

On iOS and other Darwin platforms, the built-in JavaScriptCore libraries will be used.

Android, on the other hand, does not ship JSC as part of the operating system, and so the dependency on the Android side will utilize the org.webkit:android-jsc package to bundle a native build of JavaScriptCore with the app itself. This will increase the total Android bundle size by between 5-10Mb.

This project is a Swift Package Manager module that uses the Skip plugin to build the package for both iOS and Android.

The module can be tested using the standard swift test command or by running the test target for the macOS destination in Xcode, which will run the Swift tests as well as the transpiled Kotlin JUnit tests in the Robolectric Android simulation environment.

Parity testing can be performed with skip test, which will output a table of the test results for both platforms.

The 10 most recent releases of skiptools/skip-script ↗:

• Release 1.1.0 ↗ — 2026-04-26
• Release 1.0.0 ↗ — 2025-02-07
• Release 0.6.0 ↗ — 2024-12-31
• Release 0.5.0 ↗ — 2024-08-16
• 0.4.1 ↗ — 2024-03-02
• 0.4.0 ↗ — 2024-02-05
• Release 0.3.5 ↗ — 2024-01-20
• Release 0.3.4 ↗ — 2023-12-31
• Release 0.3.3 ↗ — 2023-11-28
• Release 0.3.2 ↗ — 2023-11-21

Full history: github.com/skiptools/skip-script/releases ↗ — .atom feed ↗