static-eval is a Node.js library that evaluates statically-analyzable JavaScript expressions at build time. It's designed for use in build scripts and code transformations, taking an AST parsed by esprima and returning the evaluated result for simple expressions with declared variables. It's intended for developers working on JavaScript build tools or code analysis who need to evaluate expressions during the build process, but it should not be used for evaluating untrusted user input due to security concerns.