JS++

JS++ is a BSD-licensed programming language for web development that extends JavaScript with a sound type system. It includes imperative, object-oriented, functional, and generic programming features.

JS++ first appeared on October 8, 2011.^[1][2][3] The modern implementation was announced at DeveloperWeek 2016^[4] and released on May 31, 2016.^[5][6][7][8] The language is designed by Roger Poon and Anton Rapetov.

Since JS++ is a superset of JavaScript, declaring types for variables is optional.

int x = 1; // declares the variable x with an "internal type" (JS++ type)
var y = 2; // declares the variable y with an "external type" (JavaScript type)
bool z = true; // declares the variable z with an "internal type" (JS++ type)

JS++ features a type system that is sound.^[9][10]

JS++ is able to efficiently analyze out-of-bounds errors at compile time.^[11][12][13]

The JS++ compiler is available for Windows, Mac OS X, and Linux. The compiler generates JavaScript output.

JS++ integrates with various code editors including Visual Studio Code, Atom, and Sublime Text.^[14][15][16]

JS++ can be integrated with third-party build tools like Webpack.^[17]

• TypeScript
• PureScript