JavaScript Obfuscator - JavaScript Obfuscator is a free online tool that obfuscates your source code, preventing it from being stolen and used without permission.
Terser - JavaScript parser, mangler, optimizer and beautifier toolkit for ES6+
UglifyJS - JavaScript minifier, beautifier, mangler and parser toolkit.
Gnirts - Gnirts is a JavaScript library for obfuscating string literals by encoding them as different string literals.
Closure Compiler - The Closure Compiler is a tool for making JavaScript download and run faster.
YUI Compressor - Yahoo JS/CSS Compressor