Wait for a few months and that will start to become viable, though it probably won’t be reasonable for two or three years.
Rust 1.14, released a couple of days ago, introduced experimental support for WASM/asm.js backends. There are experiments like https://github.com/tcr/rust-todomvc which show off the possibilities. At the moment it produces a rather massive blob (over 1MB as JavaScript, not sure as WASM), but that will improve, and for some situations that doesn’t matter so much anyway.
Rust 1.14, released a couple of days ago, introduced experimental support for WASM/asm.js backends. There are experiments like https://github.com/tcr/rust-todomvc which show off the possibilities. At the moment it produces a rather massive blob (over 1MB as JavaScript, not sure as WASM), but that will improve, and for some situations that doesn’t matter so much anyway.