web-sys Overview

The web-sys crate has this file and directory layout:

.
├── build.rs
├── Cargo.toml
├── README.md
├── src
│   └── lib.rs
└── webidls
    └── enabled
        └── ...

webidls/enabled/*.webidl

These are the WebIDL interfaces that we will actually generate bindings for (or at least bindings for some of the things defined in these files).

build.rs

The build.rs invokes wasm-bindgen‘s WebIDL frontend on all the WebIDL files in webidls/enabled. It writes the resulting bindings into the cargo build’s out directory.

src/lib.rs

The only thing src/lib.rs does is include the bindings generated at compile time in build.rs. Here is the whole src/lib.rs file:

{{#include ../../../../crates/web-sys/src/lib.rs}}

Cargo features

When compiled the crate is almost empty by default, which probably isn't what you want! Due to the very large number of APIs, this crate uses features to enable portions of its API to reduce compile times. The list of features in Cargo.toml all correspond to types in the generated functions. Enabling a feature enables that type. All methods should indicate what features need to be activated to use the method.