Atwood's law
expressionweb devprogramming
'Any application that can be written in JavaScript, will eventually be written in JavaScript.'
Jeff Atwood coined it in 2007 as a half-joke about the web platform's gravity; then Node took JavaScript to servers, Electron took it to the desktop, and React Native took it to phones, and the joke became a roadmap. The law is really about reach: the runtime installed everywhere wins, quality arguments notwithstanding. Its spiritual successor is already circulating: anything that can be compiled to WebAssembly, will be.
Any application that can be written in JavaScript will eventually be written in JavaScript. Jeff Atwood's 2007 formulation was a prediction, and it has aged into an unremarkable description of reality.
The prediction came true through a mechanism worth naming: the browser was the only universal runtime, so anything that ran there ran everywhere without installation. Node put the same language on the server, Electron put it on the desktop, and React Native put it on phones. The language did not win on merit, it won on reach, which is the same dynamic that decided TCP/IP over technically superior alternatives.
WebAssembly complicates the sequel and is worth watching for that reason. It makes the browser a target for other languages, which removes the structural reason JavaScript won, and the honest question is whether reach or merit dominates when both are available. Atwood's law described an era in which there was no choice; whether it describes the next one is genuinely undecided.