* @license Choose any of Apache, MIT, GPL, LGPL */ /** * This class is meant to safely minify javascript code, while leaving syntactically correct * programs intact. Other libraries, such as JSMin require a certain coding style to work * correctly. OTOH, libraries like jsminplus, that do parse the code correctly are rather * slow, because they construct a complete parse tree before outputting the code minified. * So this class is meant to allow arbitrary (but syntactically correct) input, while being * fast enough to be used for on-the-fly minifying. */ class JavaScriptMinifier { /* Class constants */ /* Parsing states. * The state machine is only necessary to decide whether to parse a slash as division * operator or as regexp literal. * States are named after the next expected item. We only distinguish states when the * distinction is relevant for our purpose. */ const STATEMENT = 0; const CONDITION = 1; const PROPERTY_ASSIGNMENT = 2; const EXPRESSION = 3; const EXPRESSION_NO_NL = 4; // only relevant for semicolon insertion const EXPRESSION_OP = 5; const EXPRESSION_FUNC = 6; const EXPRESSION_TERNARY = 7; // used to determine the role of a colon const EXPRESSION_TERNARY_OP = 8; const EXPRESSION_TERNARY_FUNC = 9; const PAREN_EXPRESSION = 10; // expression which is not on the top level const PAREN_EXPRESSION_OP = 11; const PAREN_EXPRESSION_FUNC = 12; const PROPERTY_EXPRESSION = 13; // expression which is within an object literal const PROPERTY_EXPRESSION_OP = 14; const PROPERTY_EXPRESSION_FUNC = 15; /* Token types */ const TYPE_UN_OP = 1; // unary operators const TYPE_INCR_OP = 2; // ++ and -- const TYPE_BIN_OP = 3; // binary operators const TYPE_ADD_OP = 4; // + and - which can be either unary or binary ops const TYPE_HOOK = 5; // ? const TYPE_COLON = 6; // : const TYPE_COMMA = 7; // , const TYPE_SEMICOLON = 8; // ; const TYPE_BRACE_OPEN = 9; // { const TYPE_BRACE_CLOSE = 10; // } const TYPE_PAREN_OPEN = 11; // ( and [ const TYPE_PAREN_CLOSE = 12; // ) and ] const TYPE_RETURN = 13; // keywords: break, continue, return, throw const TYPE_IF = 14; // keywords: catch, for, with, switch, while, if const TYPE_DO = 15; // keywords: case, var, finally, else, do, try const TYPE_FUNC = 16; // keywords: function const TYPE_LITERAL = 17; // all literals, identifiers and unrecognised tokens // Sanity limit to avoid excessive memory usage const STACK_LIMIT = 1000; /* Static functions */ /** * Returns minified JavaScript code. * * NOTE: $maxLineLength isn't a strict maximum. Longer lines will be produced when * literals (e.g. quoted strings) longer than $maxLineLength are encountered * or when required to guard against semicolon insertion. * * @param string $s JavaScript code to minify * @param bool $statementsOnOwnLine Whether to put each statement on its own line * @param int $maxLineLength Maximum length of a single line, or -1 for no maximum. * @return String Minified code */ public static function minify( $s, $statementsOnOwnLine = false, $maxLineLength = 1000 ) { // First we declare a few tables that contain our parsing rules // $opChars : characters, which can be combined without whitespace in between them $opChars = array( '!' => true, '"' => true, '%' => true, '&' => true, "'" => true, '(' => true, ')' => true, '*' => true, '+' => true, ',' => true, '-' => true, '.' => true, '/' => true, ':' => true, ';' => true, '<' => true, '=' => true, '>' => true, '?' => true, '[' => true, ']' => true, '^' => true, '{' => true, '|' => true, '}' => true, '~' => true ); // $tokenTypes : maps keywords and operators to their corresponding token type $tokenTypes = array( '!' => self::TYPE_UN_OP, '~' => self::TYPE_UN_OP, 'delete' => self::TYPE_UN_OP, 'new' => self::TYPE_UN_OP, 'typeof' => self::TYPE_UN_OP, 'void' => self::TYPE_UN_OP, '++' => self::TYPE_INCR_OP, '--' => self::TYPE_INCR_OP, '!=' => self::TYPE_BIN_OP, '!==' => self::TYPE_BIN_OP, '%' => self::TYPE_BIN_OP, '%=' => self::TYPE_BIN_OP, '&' => self::TYPE_BIN_OP, '&&' => self::TYPE_BIN_OP, '&=' => self::TYPE_BIN_OP, '*' => self::TYPE_BIN_OP, '*=' => self::TYPE_BIN_OP, '+=' => self::TYPE_BIN_OP, '-=' => self::TYPE_BIN_OP, '.' => self::TYPE_BIN_OP, '/' => self::TYPE_BIN_OP, '/=' => self::TYPE_BIN_OP, '<' => self::TYPE_BIN_OP, '<<' => self::TYPE_BIN_OP, '<<=' => self::TYPE_BIN_OP, '<=' => self::TYPE_BIN_OP, '=' => self::TYPE_BIN_OP, '==' => self::TYPE_BIN_OP, '===' => self::TYPE_BIN_OP, '>' => self::TYPE_BIN_OP, '>=' => self::TYPE_BIN_OP, '>>' => self::TYPE_BIN_OP, '>>=' => self::TYPE_BIN_OP, '>>>' => self::TYPE_BIN_OP, '>>>=' => self::TYPE_BIN_OP, '^' => self::TYPE_BIN_OP, '^=' => self::TYPE_BIN_OP, '|' => self::TYPE_BIN_OP, '|=' => self::TYPE_BIN_OP, '||' => self::TYPE_BIN_OP, 'in' => self::TYPE_BIN_OP, 'instanceof' => self::TYPE_BIN_OP, '+' => self::TYPE_ADD_OP, '-' => self::TYPE_ADD_OP, '?' => self::TYPE_HOOK, ':' => self::TYPE_COLON, ',' => self::TYPE_COMMA, ';' => self::TYPE_SEMICOLON, '{' => self::TYPE_BRACE_OPEN, '}' => self::TYPE_BRACE_CLOSE, '(' => self::TYPE_PAREN_OPEN, '[' => self::TYPE_PAREN_OPEN, ')' => self::TYPE_PAREN_CLOSE, ']' => self::TYPE_PAREN_CLOSE, 'break' => self::TYPE_RETURN, 'continue' => self::TYPE_RETURN, 'return' => self::TYPE_RETURN, 'throw' => self::TYPE_RETURN, 'catch' => self::TYPE_IF, 'for' => self::TYPE_IF, 'if' => self::TYPE_IF, 'switch' => self::TYPE_IF, 'while' => self::TYPE_IF, 'with' => self::TYPE_IF, 'case' => self::TYPE_DO, 'do' => self::TYPE_DO, 'else' => self::TYPE_DO, 'finally' => self::TYPE_DO, 'try' => self::TYPE_DO, 'var' => self::TYPE_DO, 'function' => self::TYPE_FUNC ); // $goto : This is the main table for our state machine. For every state/token pair // the following state is defined. When no rule exists for a given pair, // the state is left unchanged. $goto = array( self::STATEMENT => array( self::TYPE_UN_OP => self::EXPRESSION, self::TYPE_INCR_OP => self::EXPRESSION, self::TYPE_ADD_OP => self::EXPRESSION, self::TYPE_PAREN_OPEN => self::PAREN_EXPRESSION, self::TYPE_RETURN => self::EXPRESSION_NO_NL, self::TYPE_IF => self::CONDITION, self::TYPE_FUNC => self::CONDITION, self::TYPE_LITERAL => self::EXPRESSION_OP ), self::CONDITION => array( self::TYPE_PAREN_OPEN => self::PAREN_EXPRESSION ), self::PROPERTY_ASSIGNMENT => array( self::TYPE_COLON => self::PROPERTY_EXPRESSION, self::TYPE_BRACE_OPEN => self::STATEMENT ), self::EXPRESSION => array( self::TYPE_SEMICOLON => self::STATEMENT, self::TYPE_BRACE_OPEN => self::PROPERTY_ASSIGNMENT, self::TYPE_PAREN_OPEN => self::PAREN_EXPRESSION, self::TYPE_FUNC => self::EXPRESSION_FUNC, self::TYPE_LITERAL => self::EXPRESSION_OP ), self::EXPRESSION_NO_NL => array( self::TYPE_SEMICOLON => self::STATEMENT, self::TYPE_BRACE_OPEN => self::PROPERTY_ASSIGNMENT, self::TYPE_PAREN_OPEN => self::PAREN_EXPRESSION, self::TYPE_FUNC => self::EXPRESSION_FUNC, self::TYPE_LITERAL => self::EXPRESSION_OP ), self::EXPRESSION_OP => array( self::TYPE_BIN_OP => self::EXPRESSION, self::TYPE_ADD_OP => self::EXPRESSION, self::TYPE_HOOK => self::EXPRESSION_TERNARY, self::TYPE_COLON => self::STATEMENT, self::TYPE_COMMA => self::EXPRESSION, self::TYPE_SEMICOLON => self::STATEMENT, self::TYPE_PAREN_OPEN => self::PAREN_EXPRESSION ), self::EXPRESSION_FUNC => array( self::TYPE_BRACE_OPEN => self::STATEMENT ), self::EXPRESSION_TERNARY => array( self::TYPE_BRACE_OPEN => self::PROPERTY_ASSIGNMENT, self::TYPE_PAREN_OPEN => self::PAREN_EXPRESSION, self::TYPE_FUNC => self::EXPRESSION_TERNARY_FUNC, self::TYPE_LITERAL => self::EXPRESSION_TERNARY_OP ), self::EXPRESSION_TERNARY_OP => array( self::TYPE_BIN_OP => self::EXPRESSION_TERNARY, self::TYPE_ADD_OP => self::EXPRESSION_TERNARY, self::TYPE_HOOK => self::EXPRESSION_TERNARY, self::TYPE_COMMA => self::EXPRESSION_TERNARY, self::TYPE_PAREN_OPEN => self::PAREN_EXPRESSION ), self::EXPRESSION_TERNARY_FUNC => array( self::TYPE_BRACE_OPEN => self::STATEMENT ), self::PAREN_EXPRESSION => array( self::TYPE_BRACE_OPEN => self::PROPERTY_ASSIGNMENT, self::TYPE_PAREN_OPEN => self::PAREN_EXPRESSION, self::TYPE_FUNC => self::PAREN_EXPRESSION_FUNC, self::TYPE_LITERAL => self::PAREN_EXPRESSION_OP ), self::PAREN_EXPRESSION_OP => array( self::TYPE_BIN_OP => self::PAREN_EXPRESSION, self::TYPE_ADD_OP => self::PAREN_EXPRESSION, self::TYPE_HOOK => self::PAREN_EXPRESSION, self::TYPE_COLON => self::PAREN_EXPRESSION, self::TYPE_COMMA => self::PAREN_EXPRESSION, self::TYPE_SEMICOLON => self::PAREN_EXPRESSION, self::TYPE_PAREN_OPEN => self::PAREN_EXPRESSION ), self::PAREN_EXPRESSION_FUNC => array( self::TYPE_BRACE_OPEN => self::STATEMENT ), self::PROPERTY_EXPRESSION => array( self::TYPE_BRACE_OPEN => self::PROPERTY_ASSIGNMENT, self::TYPE_PAREN_OPEN => self::PAREN_EXPRESSION, self::TYPE_FUNC => self::PROPERTY_EXPRESSION_FUNC, self::TYPE_LITERAL => self::PROPERTY_EXPRESSION_OP ), self::PROPERTY_EXPRESSION_OP => array( self::TYPE_BIN_OP => self::PROPERTY_EXPRESSION, self::TYPE_ADD_OP => self::PROPERTY_EXPRESSION, self::TYPE_HOOK => self::PROPERTY_EXPRESSION, self::TYPE_COMMA => self::PROPERTY_ASSIGNMENT, self::TYPE_PAREN_OPEN => self::PAREN_EXPRESSION ), self::PROPERTY_EXPRESSION_FUNC => array( self::TYPE_BRACE_OPEN => self::STATEMENT ) ); // $push : This table contains the rules for when to push a state onto the stack. // The pushed state is the state to return to when the corresponding // closing token is found $push = array( self::STATEMENT => array( self::TYPE_BRACE_OPEN => self::STATEMENT, self::TYPE_PAREN_OPEN => self::EXPRESSION_OP ), self::CONDITION => array( self::TYPE_PAREN_OPEN => self::STATEMENT ), self::PROPERTY_ASSIGNMENT => array( self::TYPE_BRACE_OPEN => self::PROPERTY_ASSIGNMENT ), self::EXPRESSION => array( self::TYPE_BRACE_OPEN => self::EXPRESSION_OP, self::TYPE_PAREN_OPEN => self::EXPRESSION_OP ), self::EXPRESSION_NO_NL => array( self::TYPE_BRACE_OPEN => self::EXPRESSION_OP, self::TYPE_PAREN_OPEN => self::EXPRESSION_OP ), self::EXPRESSION_OP => array( self::TYPE_HOOK => self::EXPRESSION, self::TYPE_PAREN_OPEN => self::EXPRESSION_OP ), self::EXPRESSION_FUNC => array( self::TYPE_BRACE_OPEN => self::EXPRESSION_OP ), self::EXPRESSION_TERNARY => array( self::TYPE_BRACE_OPEN => self::EXPRESSION_TERNARY_OP, self::TYPE_PAREN_OPEN => self::EXPRESSION_TERNARY_OP ), self::EXPRESSION_TERNARY_OP => array( self::TYPE_HOOK => self::EXPRESSION_TERNARY, self::TYPE_PAREN_OPEN => self::EXPRESSION_TERNARY_OP ), self::EXPRESSION_TERNARY_FUNC => array( self::TYPE_BRACE_OPEN => self::EXPRESSION_TERNARY_OP ), self::PAREN_EXPRESSION => array( self::TYPE_BRACE_OPEN => self::PAREN_EXPRESSION_OP, self::TYPE_PAREN_OPEN => self::PAREN_EXPRESSION_OP ), self::PAREN_EXPRESSION_OP => array( self::TYPE_PAREN_OPEN => self::PAREN_EXPRESSION_OP ), self::PAREN_EXPRESSION_FUNC => array( self::TYPE_BRACE_OPEN => self::PAREN_EXPRESSION_OP ), self::PROPERTY_EXPRESSION => array( self::TYPE_BRACE_OPEN => self::PROPERTY_EXPRESSION_OP, self::TYPE_PAREN_OPEN => self::PROPERTY_EXPRESSION_OP ), self::PROPERTY_EXPRESSION_OP => array( self::TYPE_PAREN_OPEN => self::PROPERTY_EXPRESSION_OP ), self::PROPERTY_EXPRESSION_FUNC => array( self::TYPE_BRACE_OPEN => self::PROPERTY_EXPRESSION_OP ) ); // $pop : Rules for when to pop a state from the stack $pop = array( self::STATEMENT => array( self::TYPE_BRACE_CLOSE => true ), self::PROPERTY_ASSIGNMENT => array( self::TYPE_BRACE_CLOSE => true ), self::EXPRESSION => array( self::TYPE_BRACE_CLOSE => true ), self::EXPRESSION_NO_NL => array( self::TYPE_BRACE_CLOSE => true ), self::EXPRESSION_OP => array( self::TYPE_BRACE_CLOSE => true ), self::EXPRESSION_TERNARY_OP => array( self::TYPE_COLON => true ), self::PAREN_EXPRESSION => array( self::TYPE_PAREN_CLOSE => true ), self::PAREN_EXPRESSION_OP => array( self::TYPE_PAREN_CLOSE => true ), self::PROPERTY_EXPRESSION => array( self::TYPE_BRACE_CLOSE => true ), self::PROPERTY_EXPRESSION_OP => array( self::TYPE_BRACE_CLOSE => true ) ); // $semicolon : Rules for when a semicolon insertion is appropriate $semicolon = array( self::EXPRESSION_NO_NL => array( self::TYPE_UN_OP => true, self::TYPE_INCR_OP => true, self::TYPE_ADD_OP => true, self::TYPE_BRACE_OPEN => true, self::TYPE_PAREN_OPEN => true, self::TYPE_RETURN => true, self::TYPE_IF => true, self::TYPE_DO => true, self::TYPE_FUNC => true, self::TYPE_LITERAL => true ), self::EXPRESSION_OP => array( self::TYPE_UN_OP => true, self::TYPE_INCR_OP => true, self::TYPE_BRACE_OPEN => true, self::TYPE_RETURN => true, self::TYPE_IF => true, self::TYPE_DO => true, self::TYPE_FUNC => true, self::TYPE_LITERAL => true ) ); // Rules for when newlines should be inserted if // $statementsOnOwnLine is enabled. // $newlineBefore is checked before switching state, // $newlineAfter is checked after $newlineBefore = array( self::STATEMENT => array( self::TYPE_BRACE_CLOSE => true, ), ); $newlineAfter = array( self::STATEMENT => array( self::TYPE_BRACE_OPEN => true, self::TYPE_PAREN_CLOSE => true, self::TYPE_SEMICOLON => true, ), ); // $divStates : Contains all states that can be followed by a division operator $divStates = array( self::EXPRESSION_OP => true, self::EXPRESSION_TERNARY_OP => true, self::PAREN_EXPRESSION_OP => true, self::PROPERTY_EXPRESSION_OP => true ); // Here's where the minifying takes place: Loop through the input, looking for tokens // and output them to $out, taking actions to the above defined rules when appropriate. $out = ''; $pos = 0; $length = strlen( $s ); $lineLength = 0; $newlineFound = true; $state = self::STATEMENT; $stack = array(); $last = ';'; // Pretend that we have seen a semicolon yet while( $pos < $length ) { // First, skip over any whitespace and multiline comments, recording whether we // found any newline character $skip = strspn( $s, " \t\n\r\xb\xc", $pos ); if( !$skip ) { $ch = $s[$pos]; if( $ch === '/' && substr( $s, $pos, 2 ) === '/*' ) { // Multiline comment. Search for the end token or EOT. $end = strpos( $s, '*/', $pos + 2 ); $skip = $end === false ? $length - $pos : $end - $pos + 2; } } if( $skip ) { // The semicolon insertion mechanism needs to know whether there was a newline // between two tokens, so record it now. if( !$newlineFound && strcspn( $s, "\r\n", $pos, $skip ) !== $skip ) { $newlineFound = true; } $pos += $skip; continue; } // Handle C++-style comments and html comments, which are treated as single line // comments by the browser, regardless of whether the end tag is on the same line. // Handle --> the same way, but only if it's at the beginning of the line if( ( $ch === '/' && substr( $s, $pos, 2 ) === '//' ) || ( $ch === '<' && substr( $s, $pos, 4 ) === '' ) ) { $pos += strcspn( $s, "\r\n", $pos ); continue; } // Find out which kind of token we're handling. $end will point past the end of it. $end = $pos + 1; // Handle string literals if( $ch === "'" || $ch === '"' ) { // Search to the end of the string literal, skipping over backslash escapes $search = $ch . '\\'; do{ $end += strcspn( $s, $search, $end ) + 2; } while( $end - 2 < $length && $s[$end - 2] === '\\' ); $end--; // We have to distinguish between regexp literals and division operators // A division operator is only possible in certain states } elseif( $ch === '/' && !isset( $divStates[$state] ) ) { // Regexp literal, search to the end, skipping over backslash escapes and // character classes for( ; ; ) { do{ $end += strcspn( $s, '/[\\', $end ) + 2; } while( $end - 2 < $length && $s[$end - 2] === '\\' ); $end--; if( $end - 1 >= $length || $s[$end - 1] === '/' ) { break; } do{ $end += strcspn( $s, ']\\', $end ) + 2; } while( $end - 2 < $length && $s[$end - 2] === '\\' ); $end--; }; // Search past the regexp modifiers (gi) while( $end < $length && ctype_alpha( $s[$end] ) ) { $end++; } } elseif( $ch === '0' && ($pos + 1 < $length) && ($s[$pos + 1] === 'x' || $s[$pos + 1] === 'X' ) ) { // Hex numeric literal $end++; // x or X $len = strspn( $s, '0123456789ABCDEFabcdef', $end ); if ( !$len ) { return self::parseError($s, $pos, 'Expected a hexadecimal number but found ' . substr( $s, $pos, 5 ) . '...' ); } $end += $len; } elseif( ctype_digit( $ch ) || ( $ch === '.' && $pos + 1 < $length && ctype_digit( $s[$pos + 1] ) ) ) { $end += strspn( $s, '0123456789', $end ); $decimal = strspn( $s, '.', $end ); if ($decimal) { if ( $decimal > 2 ) { return self::parseError($s, $end, 'The number has too many decimal points' ); } $end += strspn( $s, '0123456789', $end + 1 ) + $decimal; } $exponent = strspn( $s, 'eE', $end ); if( $exponent ) { if ( $exponent > 1 ) { return self::parseError($s, $end, 'Number with several E' ); } $end++; // + sign is optional; - sign is required. $end += strspn( $s, '-+', $end ); $len = strspn( $s, '0123456789', $end ); if ( !$len ) { return self::parseError($s, $pos, 'No decimal digits after e, how many zeroes should be added?' ); } $end += $len; } } elseif( isset( $opChars[$ch] ) ) { // Punctuation character. Search for the longest matching operator. while( $end < $length && isset( $tokenTypes[substr( $s, $pos, $end - $pos + 1 )] ) ) { $end++; } } else { // Identifier or reserved word. Search for the end by excluding whitespace and // punctuation. $end += strcspn( $s, " \t\n.;,=<>+-{}()[]?:*/%'\"!&|^~\xb\xc\r", $end ); } // Now get the token type from our type array $token = substr( $s, $pos, $end - $pos ); // so $end - $pos == strlen( $token ) $type = isset( $tokenTypes[$token] ) ? $tokenTypes[$token] : self::TYPE_LITERAL; if( $newlineFound && isset( $semicolon[$state][$type] ) ) { // This token triggers the semicolon insertion mechanism of javascript. While we // could add the ; token here ourselves, keeping the newline has a few advantages. $out .= "\n"; $state = self::STATEMENT; $lineLength = 0; } elseif( $maxLineLength > 0 && $lineLength + $end - $pos > $maxLineLength && !isset( $semicolon[$state][$type] ) && $type !== self::TYPE_INCR_OP ) { // This line would get too long if we added $token, so add a newline first. // Only do this if it won't trigger semicolon insertion and if it won't // put a postfix increment operator on its own line, which is illegal in js. $out .= "\n"; $lineLength = 0; // Check, whether we have to separate the token from the last one with whitespace } elseif( !isset( $opChars[$last] ) && !isset( $opChars[$ch] ) ) { $out .= ' '; $lineLength++; // Don't accidentally create ++, -- or // tokens } elseif( $last === $ch && ( $ch === '+' || $ch === '-' || $ch === '/' ) ) { $out .= ' '; $lineLength++; } $out .= $token; $lineLength += $end - $pos; // += strlen( $token ) $last = $s[$end - 1]; $pos = $end; $newlineFound = false; // Output a newline after the token if required // This is checked before AND after switching state $newlineAdded = false; if ( $statementsOnOwnLine && !$newlineAdded && isset( $newlineBefore[$state][$type] ) ) { $out .= "\n"; $lineLength = 0; $newlineAdded = true; } // Now that we have output our token, transition into the new state. if( isset( $push[$state][$type] ) && count( $stack ) < self::STACK_LIMIT ) { $stack[] = $push[$state][$type]; } if( $stack && isset( $pop[$state][$type] ) ) { $state = array_pop( $stack ); } elseif( isset( $goto[$state][$type] ) ) { $state = $goto[$state][$type]; } // Check for newline insertion again if ( $statementsOnOwnLine && !$newlineAdded && isset( $newlineAfter[$state][$type] ) ) { $out .= "\n"; $lineLength = 0; } } return $out; } static function parseError($fullJavascript, $position, $errorMsg) { // TODO: Handle the error: trigger_error, throw exception, return false... return false; } }