Terser vs TypeScript Playground

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.

TypeScript Playground is a free browser environment for writing, running, sharing, and safely experimenting with TypeScript and JavaScript. It accepts .ts, .tsx, .js, .jsx, and .d.ts files. Run converts code to JavaScript, executes it in the current browser session, and shows console output in Logs; the browser session can also support DOM API experiments. The editor centers on one text document and is described as a teaching tool that needs no setup. Users can select supported TypeScript builds, including beta, nightly, pull request, and older builds. The TS Config panel exposes a focused compiler-option set, while twoslash annotations can configure options beyond it. URLs can preserve code, compiler flags, and settings for sharing. Export can create Markdown, open TypeScript AST Viewer, or export a project to CodeSandbox or StackBlitz. Plugins are supported, including Presentation Mode, Clippy, TSQuery, Collaborate, and Transformer. The mobile layout uses a single pane and does not show transpiled JavaScript beside source.