wasm-bindgen/guide/src/cli-reference.md

CLI Reference

The wasm-bindgen tool has a number of options available to it to tweak the JS that is generated. By default the generated JS uses ES modules and is compatible with both Node and browsers (but will likely require a bundler for both use cases).

Supported flags of the CLI tool can be learned via wasm-bindgen --help, but some notable options are:

• --nodejs: this flag will tailor output for Node instead of browsers, allowing for native usage of require of the generated JS and internally using require instead of ES modules. When using this flag no further postprocessing (aka a bundler) should be necessary to work with the wasm.

• --browser: this flag will tailor the output specifically for browsers, making it incompatible with Node. This will basically make the generated JS a tiny bit smaller as runtime checks for Node won't be necessary.

• --no-modules: the default output of wasm-bindgen uses ES modules but this option indicates that ES modules should not be used and output should be tailored for a web browser. In this mode window.wasm_bindgen will be a function that takes a path to the wasm file to fetch and instantiate. Afterwards exported functions from the wasm are available through window.wasm_bindgen.foo. Note that the name wasm_bindgen can be configured with the --no-modules-global FOO flag.

• --no-typescript: by default a *.d.ts file is generated for the generated JS file, but this flag will disable generating this TypeScript file.

• --debug: generates a bit more JS and wasm in "debug mode" to help catch programmer errors, but this output isn't intended to be shipped to production