React, Flux, GraphQL, Hack, HHVM...? All of this and more!
This advantage is unique to WebAssembly and is another interesting reason why you may want to look into compiling mundane UI code such as React, Svelte, etc. to WebAssembly.
For Node.js the advantage is not there as it is run as a continuous process. Unless the Wasm provides a better runtime or capability performance otherwise, there is no inherent benefit because of streaming compilation - aside from a shorter startup time, which is insignificant in most cases.