| # The `wasm-bindgen` Command Line Interface |
| |
| The `wasm-bindgen` command line tool has a number of options available to it to |
| tweak the JavaScript that is generated. The most up-to-date set of flags can |
| always be listed via `wasm-bindgen --help`. |
| |
| ## Installation |
| |
| ``` |
| cargo install -f wasm-bindgen-cli |
| ``` |
| |
| ## Usage |
| |
| ``` |
| wasm-bindgen [options] ./target/wasm32-unknown-unknown/release/crate.wasm |
| ``` |
| |
| ## Options |
| |
| ### `--out-dir DIR` |
| |
| The target directory to emit the JavaScript bindings, TypeScript definitions, |
| processed `.wasm` binary, etc... |
| |
| ### `--target` |
| |
| This flag indicates what flavor of output what `wasm-bindgen` should generate. |
| For example it could generate code to be loaded in a bundler like Webpack, a |
| native web page, or Node.js. For a full list of options to pass this flag, see |
| the section on [deployment] |
| |
| [deployment]: deployment.html |
| |
| ### `--no-modules-global VAR` |
| |
| When `--target no-modules` is used this flag can indicate what the name of the |
| global to assign generated bindings to. |
| |
| For more information about this see the section on [deployment] |
| |
| ### `--typescript` |
| |
| Output a TypeScript declaration file for the generated JavaScript bindings. This |
| is on by default. |
| |
| ### `--no-typescript` |
| |
| By default, a `*.d.ts` TypeScript declaration file is generated for the |
| generated JavaScript bindings, but this flag will disable that. |
| |
| ### `--omit-imports` |
| |
| When the `module` attribute is used with the `wasm-bindgen` macro, the code |
| generator will emit corresponding `import` or `require` statements in the header |
| section of the generated javascript. This flag causes those import statements to |
| be omitted. This is necessary for some use cases, such as generating javascript |
| which is intended to be used with Electron (with node integration disabled), |
| where the imports are instead handled through a separate preload script. |
| |
| ### `--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. |
| |
| ### `--no-demangle` |
| |
| When post-processing the `.wasm` binary, do not demangle Rust symbols in the |
| "names" custom section. |
| |
| ### `--keep-debug` |
| |
| When post-processing the `.wasm` binary, do not strip DWARF debug info custom |
| sections. |
| |
| ### `--browser` |
| |
| When generating bundler-compatible code (see the section on [deployment]) this |
| indicates that the bundled code is always intended to go into a browser so a few |
| checks for Node.js can be elided. |
| |
| ### `--weak-refs` |
| |
| Enables usage of the [TC39 Weak References |
| proposal](https://github.com/tc39/proposal-weakrefs), ensuring that all Rust |
| memory is eventually deallocated regardless of whether you're calling `free` or |
| not. This is off-by-default while we're waiting for support to percolate into |
| all major browsers. For more information see the [documentation about weak |
| references](./weak-references.md). |
| |
| ### `--reference-types` |
| |
| Enables usage of the [WebAssembly References Types |
| proposal](https://github.com/webassembly/reference-types) proposal, meaning that |
| the WebAssembly binary will use `externref` when importing and exporting |
| functions that work with `JsValue`. For more information see the [documentation |
| about reference types](./reference-types.md). |
| |
| ### `--omit-default-module-path` |
| |
| Don't add WebAssembly fallback imports in generated JavaScript. |
