Static TypeScript An Implementation of a Static Compiler for the TypeScript Language

While the programming of microcontroller-based embeddable devices typically is the realm of the C language, such devices are now finding their way into the classroom for CS education, even at the level of middle school. As a result, the use of scripting languages (such as JavaScript and Python) for microcontrollers is on the rise. We present Static TypeScript (STS), a subset of TypeScript (itself, a gradually typed superset of JavaScript), and its compiler/linker toolchain, which is implemented fully in TypeScript and runs in the web browser. STS is designed to be useful in practice (especially in education), while being amenable to static compilation targeting small devices. A user's STS program is compiled to machine code in the browser and linked against a precompiled C++ runtime, producing an executable that is more efficient than the prevalent embedded interpreter approach, extending battery life and making it possible to run on devices with as little as 16 kB of RAM (such as the BBC micro:bit). This paper is primarily a description of the STS system and the technical challenges of implementing embedded programming platforms in the classroom.