Which came first, JavaScript or TikTok?

JavaScript came first, by 21 years. Brendan Eich wrote it in ten days for Netscape Navigator.

Side by side

JavaScript

JavaScript was written in about ten days in May 1995, shipped in Netscape Navigator 2.0 later that year, and was called LiveScript until December, when Netscape renamed it as part of a marketing deal with Sun. It has nothing to do with Java beyond some borrowed syntax. Standardisation as ECMAScript followed in 1997, and the language spent a decade being treated as a toy before it became the most widely deployed programming language in the world.

TikTok

The app launched in China as Douyin in September 2016 and internationally as TikTok in 2017. What made it global was the 2018 acquisition and merger of Musical.ly, a lip-sync app that had launched in 2014 and already had a large Western user base — so part of TikTok is two years older than TikTok. Douyin and TikTok remain separate apps on separate infrastructure.