javascript minifier written in javascript (todo);

jsmin.js

var jsmin = function (js_string) {
    js_min = {
        holder: '/*wenjun.yan*/',             // the minified js
        pos: 0,                 // current position
        chr: ' ',               // current char
        js_string: js_string,   // unminified js 

        specs: ["'", '"', '{', '}', '(', ')',
                '[', ']', '+', '-', '*', '/',
                ':', '?', '!', '|', '&', '\\',';'],
        
        // exit and show error message;
        error: function () {
            throw "Error! current position: " + this.pos +
                " current char: " + this.chr + 
                " \n the holder value : " + this.holder;
        },
        
        // check if current char is ' or "
        is_string: function () {
            return this.chr === '"' || this.chr === "'";
        },
        
        // check if current char is in a specs table 
        is_special: function () {
            return this.specs.indexOf(this.chr) > -1? true: false;
        },
        
        // check if current char is a digit
        is_word: function () {
            var chr = this.chr;
            return (chr > '0' && chr < '9') ||
                (chr > 'a' && chr < 'z') ||
                (chr > 'A' && chr < 'Z') ||
                chr === '$' || chr === '_' ||
                chr.charCodeAt(0) > 126;
        },
        
        // check if current char is blank of any kind
        is_blank: function () {
            return ' \t\r\n\v'.indexOf(this.chr) > -1? true: false;
        },
        
        // check if the current char is the beginning of a comment;
        is_comment: function () {
            var t = this.peek();
            if (this.chr === '/' && (t === '*' || t === '/')) {
                this.next();
                return true;
            }
            return false;
        },

        // save the whole string into holder;
        string: function () {
            this.save();
            var s = '';
            var string = '';

            if (this.chr === '"') {
                s = this.chr;
            }

            if (this.chr === "'") {
                s = this.chr;
            }

            if (!s) {
                console.log("error1");
                this.error();
            }

            while(!(this.chr !== '\\' && this.next().chr === s)) {
                this.save();
            }
            return this.save('"').next();
        },
                


        // skip the special chars and following blanks
        // undone!!
        special: function () {
            return this.save().blank();
        },
            
        // skip the comment;
        comment: function () {
            var tmp = this.next().chr;
            if (tmp === '/') {
                while(this.next().chr !== '\n') {}
                return this.next();
            } else if (tmp === '*') {
                while(this.next().chr) {
                    if (this.next().chr === '/') {
                        return this.next();
                    }
                }
                console.log("error2");
                this.error();
            } else {
                console.log("error3");
                this.error();
            }
        },
        
        // skip the word (any javascript word) and save it;
        word: function () {
            var tmp = chr;
            while(this.next().chr) {
                tmp += this.chr;
            }
            return this.save(tmp);
        },

        // skip blank;
        blank: function () {
            console.log("stepin blank: " + this.chr);
            while (this.next().is_blank()) {console.log(this.chr);}
            console.log("stepout blank: " + this.chr);
            return this;
        },
        
        // get next char and update the pos and chr
        next: function () {
            console.log ("step in next: " + this.chr);
            this.pos += 1;
            this.chr = this.js_string[this.pos];
            console.log ("step out next: " + this.chr);
            return this;
        },
        
        // get the next char but not update the pos and chr
        peek: function () {
            return this.js_string[this.pos+1];
        },
        
        // save the current char or the word (if there is) to holder
        save: function (word) {
            if (word) {
                this.holder += word;
            } else {
                this.holder += this.chr;
            }
            return this;
        },
        
        // run 
        run: function () {
            // state stands for the type of the last saved token
            // 0: specs
            // 1: word, string
            var state = 0;
            while(this.pos <= this.js_string.length) {
                console.log("WHILE current char : " + this.chr,this.peek());
                if (this.is_blank()) {
                    this.blank();
                    console.log("BLANK current char : " + this.chr);
                    
                } else if (this.is_string()) {
                    console.log("STRING current char : " + this.chr);
                    if (state !== 0) {
                        this.save(' ');
                        state = 1;
                    }
                    this.string();
                    
                } else if (this.is_special()) {
                    console.log("SPECIAL current char : " + this.chr);
                    state = 0;
                    this.special();
                    
                } else if (this.is_comment()) {
                    console.log("COMMENT current char : " + this.chr);
                    this.comment();
                    
                } else if (this.is_word()) {
                    console.log("WORD current char : " + this.chr);
                    if (state !== 0) {
                        this.save(' ');
                        state = 1;
                    }
                    this.word();

                } else {
                    console.log("ERROR current char : " + this.chr);
                    console.log("error4");
                    this.error();
                }
            }
            return this.holder;
        }
    };
    
    return js_min.run();
};


// comment: skip to the end;
// string: skip to the end of the string and save it;
// special: save it and then skip all following blank;
// word: skip to the end of the word, temp it at the same time. Then save it;


js_str = "var   a  = 1;"
console.log(jsmin(js_str));