SlimIt - JavaScript minifier
Project description
Welcome to SlimIt
SlimIt is a JavaScript minifier written in Python. It compiles JavaScript into more compact code so that it downloads and runs faster.
SlimIt also provides a library that includes a JavaScript parser, lexer, pretty printer and a tree visitor.
Let’s minify some code
From the command line:
$ slimit -h Usage: slimit [options] [input file] If no input file is provided STDIN is used by default. Minified JavaScript code is printed to STDOUT. Options: -h, --help show this help message and exit -m, --mangle mangle names $ cat test.js var a = function( obj ) { for ( var name in obj ) { return false; } return true; }; $ $ slimit --mangle < test.js var a=function(a){for(var b in a)return false;return true;};
Or using library API:
>>> from slimit import minify >>> text = """ ... var a = function( obj ) { ... for ( var name in obj ) { ... return false; ... } ... return true; ... }; ... """ >>> print minify(text, mangle=True) var a=function(a){for(var b in a)return false;return true;};
Iterate over, modify a JavaScript AST and pretty print it
>>> from slimit.parser import Parser >>> from slimit.visitors import nodevisitor >>> from slimit import ast >>> >>> parser = Parser() >>> tree = parser.parse('for(var i=0; i<10; i++) {var x=5+i;}') >>> for node in nodevisitor.visit(tree): ... if isinstance(node, ast.Identifier) and node.value == 'i': ... node.value = 'hello' ... >>> print tree.to_ecma() # print awesome javascript :) for (var hello = 0; hello < 10; hello++) { var x = 5 + hello; } >>>
Using lexer in your project
>>> from slimit.lexer import Lexer >>> lexer = Lexer() >>> lexer.input('a = 1;') >>> for token in lexer: ... print token ... LexToken(ID,'a',1,0) LexToken(EQ,'=',1,2) LexToken(NUMBER,'1',1,4) LexToken(SEMI,';',1,5)
You can get one token at a time using token method:
>>> lexer.input('a = 1;') >>> while True: ... token = lexer.token() ... if not token: ... break ... print token ... LexToken(ID,'a',1,0) LexToken(EQ,'=',1,2) LexToken(NUMBER,'1',1,4) LexToken(SEMI,';',1,5)
LexToken instance has different attributes:
>>> lexer.input('a = 1;') >>> token = lexer.token() >>> token.type, token.value, token.lineno, token.lexpos ('ID', 'a', 1, 0)
Installation
Using pip:
$ sudo pip install slimit
Using easy_install:
$ sudo easy_install slimit
Benchmarks
jQuery 1.6.1 (bytes) |
jsmin |
rJSmin |
SlimIt |
---|---|---|---|
234,995 |
134,819 |
134,215 |
94,290 |
Roadmap
More minifications
Speed improvements
Change History
0.5.1 (2011-06-06)
0.5 (2011-06-06)
Added name mangling
0.4 (2011-05-12)
Minify more by removing block braces { }
More tests
0.3.2 (2011-05-09)
More hacks to use pre-generated lex and yacc tables when called from the command line
0.3.1 (2011-05-09)
Use pre-generated lex and yacc tables when called from the command line
0.3 (2011-05-09)
Added minifier
0.2 (2011-05-07)
Added a JavaScript parser
Added pretty printer
Added node visitor
0.1 (2011-05-02)
Initial public version. It contains only a JavaScript lexer
Project details
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