JavaScript interoperability

Integrate JavaScript libraries and APIs into Dart web apps.

The Dart web platform provides tools to call JavaScript from Dart and Dart from JavaScript, bringing the JavaScript ecosystem directly to Dart code.

Find getting-started resources, usage guides, and dart:js_interop library documentation for calling JavaScript libraries, interacting with browser APIs, and compiling web apps to WebAssembly (Wasm).

Get started with JS interop:

• Get started with JavaScript interop
• How to mock JavaScript interop objects

Review the reference guides:

• Usage reference
• JS types reference

Interact with the browser:

• package:web and migration

When compiling Dart web apps to WebAssembly (dart compile wasm), keep these interoperability and performance practices in mind:

• Use dart:js_interop and package:web: Deprecated legacy web and interop libraries (dart:html, dart:js, dart:js_util, and package:js) are unsupported on Wasm targets.
• Minimize high-frequency calls across the Wasm and JS boundary: In performance-critical code or tight loops, keep computation in Dart or batch values rather than making repeated interop calls per iteration.
• Find Wasm-compatible packages: Use the wasm-ready filter on pub.dev to verify that packages use dart:js_interop and package:web.

Explore previous JavaScript interop libraries:

• Past JS interop

Explore the API reference documentation:

• dart:js_interop API reference
• dart:js_interop_unsafe API reference