Babel REPL vs Terser

Babel REPL has no write-up on Specifiction yet; its figures are above.

Terser is a free, open-source JavaScript minifier that reduces code by shortening variable names, removing whitespace and comments, and dropping unused code. It can be used through a command-line interface or Node.js API; browser loading is supported and exposes a global `Terser` variable with a `.minify` property. The API’s `minify()` enables compression and mangling by default, and both settings can be changed or turned off. The API can return a source map, while the CLI can generate source maps for compressed JavaScript. The CLI accepts multiple input files and parses them in sequence in one global scope, or reads from standard input when no input file is specified. Compatibility options include an ECMAScript target; `ecma` defaults to 5 for compression and output formatting. Property-name mangling can break code, so the documentation says to use it only when its behavior is understood. Built-in DOM property mangling is disabled by default and is not recommended for enabling. Terser also supports Acorn-produced SpiderMonkey AST input and a Yarn resolution alias for nested `uglify-es` dependencies.