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JavaScript golfers got their own shorthand in 2015 when Code Golf Stack Exchange user ETHproductions created Japt, a language that transpiles to JavaScript while stripping away nearly all of its ceremony. Variables U through Z are prefilled with inputs, methods are single characters, closing parentheses and quotes can be omitted, and the result of the final expression is printed automatically. Later stewardship by community member Shaggy added shortcuts and kept the interpreter current, and Japt remains a regular sight in Code Golf Stack Exchange answer lists. Because XCODX executes it in a genuine interactive terminal, you can experiment with how Japt receives input and emits output live, without opening the web interpreter or installing Node tooling.
"Hello, World!"
How it works: a Japt program's final expression is implicitly printed, so a lone string literal outputs the greeting. In larger programs the trailing quote could even be dropped, since Japt closes unterminated literals at the end of the program.Japt is the natural upgrade path for golfers who already think in JavaScript: array methods, template-style string interpolation, and arrow-like function blocks all have one-character forms, so porting a JS answer often halves its byte count. It suits string manipulation and number-list challenges especially well, and reading a Japt answer next to its transpiled JavaScript is an effective way to teach how much of everyday syntax is compressible ceremony.
No, it is a distinct language that compiles to JavaScript. Beyond shortening names, Japt changes the grammar: implicit input variables, implicit output of the last expression, auto-closing of strings and parentheses, and a library of golf-oriented built-ins with no JS equivalent. Minification preserves semantics of existing code; Japt gives you different, denser semantics to write in.
Inputs are parsed and bound to the variables U, V, W, and X in order, so most programs never mention reading at all; they simply use U where a JavaScript program would declare a parameter. Flags can alter parsing, and full stdin is available for programs that want raw text. Implicit input plus implicit output removes almost all I/O bytes.
Japt scores in printable ASCII with some multibyte shortcuts, so on pure byte count Jelly, 05AB1E, and Vyxal usually edge it out. It stays competitive on string-heavy and object-manipulation tasks where its JavaScript heritage supplies strong built-ins, and it frequently beats mainstream languages by wide margins while remaining far easier to pick up than a codepage language.
Code Golf Stack Exchange user ETHproductions created Japt in 2015 as a JavaScript-golfing shorthand. Community member Shaggy later took over stewardship, adding shortcuts and keeping the interpreter current, which is why Japt still shows up regularly in answer lists rather than having stalled the way some older golfing languages did.
Automatically, from the final expression. Whatever the last expression evaluates to gets printed, so most Japt programs contain no print or console.log at all; they simply end with the value they want to show. Combined with inputs pre-bound to variables, this implicit output removes nearly all of the I/O boilerplate a JavaScript answer would carry.
No, and leaving them off is a standard golfing move. Japt lets you omit trailing closing parentheses and quotation marks because the parser can infer them at the end of the program, so you save a byte for each one you drop. It is one of several ways Japt strips the ceremony out of ordinary JavaScript.
main.japtplain text — no highlighter ships for this languageno standard input construct"Hello from Japt!"