The goal of wasm-js-cstdlib is to provide a standalone javascript implementation of a subset of the C Standard Library, which can be imported into a WebAssembly module. File I/O can be configured to emulate a file operations using either HTTP REST operations with an included server, or the local storage API, or a combination of both. Some things like socket I/O will be stubbed.
dylwhich/wasm-js-cstdlib
pure javascript implementation of libc for linking into wasm, without emscripten
C