Communicate with JavaScript

Melange interoperates very well with JavaScript, and provides a wide array of features to create bindings to JavaScript code. A binding is a piece of code that references a JavaScript object or value and makes it available for use in Melange code. A very basic example of a binding is:

external confirm : string -> bool = "window.confirm"

external confirm: string => bool = "window.confirm";

The above code binds JavaScript's window.confirm function to a Melange function named confirm. Note how the binding includes type annotations so that there's no ambiguity about the types of the arguments and return value.

---

In this section:

• Language concepts: Learn about the language features that make bindings possible
• Data types and runtime representations: See how Melange types map to JavaScript runtime types
• Melange attributes and extension nodes: A reference of all the built-in attributes and extension nodes that can be used to create bindings
• Working with JavaScript objects and values: A rundown of all the common scenarios when binding to JavaScript objects and values (including functions)
• Advanced JavaScript interoperability: Advanced topics such as code generation using @deriving
• Bindings cookbook: A collection of recipes that show JavaScript snippets and the equivalent code in Melange