There's a fair bit of work in this area that leverages Flow type syntax, e.g: - https://github.com/gcanti/tcomb https://github.com/gcanti/tcomb - https://gith

There's a fair bit of work in this area that leverages Flow type syntax, e.g: - https://github.com/gcanti/tcomb https://github.com/gcanti/tcomb - https://github.com/gcanti/io-ts https://github.com/gcanti/io-ts (for typescript) - https://github.com/codemix/flow-runtime https://github.com/codemix/flow-runtime (i wrote this) And another alternative is to use Design by Contract, like Eiffel: https://github.com/codemix/babel-plugin-contracts https://github.com/codemix/babel-plugin-contracts (also me)