format JSON

white-space: pre;

var formatJson = function(json, options) {
    var reg = null,
        formatted = '',
        pad = 0,
        PADDING = '    '; // one can also use '\t' or a different number of spaces

    // optional settings
    options = options || {};
    // remove newline where '{' or '[' follows ':'
    options.newlineAfterColonIfBeforeBraceOrBracket = (options.newlineAfterColonIfBeforeBraceOrBracket === true) ? true : false;
    // use a space after a colon
    options.spaceAfterColon = (options.spaceAfterColon === false) ? false : true;

    // begin formatting...
    if (typeof json !== 'string') {
        // make sure we start with the JSON as a string
        json = JSON.stringify(json);
    } else {
        // is already a string, so parse and re-stringify in order to remove extra whitespace
        json = JSON.parse(json);
        json = JSON.stringify(json);
    }

    // add newline before and after curly braces
    reg = /([\{\}])/g;
    json = json.replace(reg, '\r\n$1\r\n');

    // add newline before and after square brackets
    reg = /([\[\]])/g;
    json = json.replace(reg, '\r\n$1\r\n');

    // add newline after comma
    reg = /(\,)/g;
    json = json.replace(reg, '$1\r\n');

    // remove multiple newlines
    reg = /(\r\n\r\n)/g;
    json = json.replace(reg, '\r\n');

    // remove newlines before commas
    reg = /\r\n\,/g;
    json = json.replace(reg, ',');

    // optional formatting...
    if (!options.newlineAfterColonIfBeforeBraceOrBracket) {         
        reg = /\:\r\n\{/g;
        json = json.replace(reg, ':{');
        reg = /\:\r\n\[/g;
        json = json.replace(reg, ':[');
    }
    if (options.spaceAfterColon) {          
        reg = /\:/g;
        json = json.replace(reg, ': ');
    }
    
    json.split('\r\n').forEach(function(node, index, array){
        var i = 0,
            indent = 0,
            padding = '';

        if (node.match(/\{$/) || node.match(/\[$/)) {
            indent = 1;
        } else if (node.match(/\}/) || node.match(/\]/)) {
            if (pad !== 0) {
                pad -= 1;
            }
        } else {
            indent = 0;
        }

        for (i = 0; i < pad; i++) {
            padding += PADDING;
        }

        formatted += padding + node + '\r\n';
        pad += indent;
    });

    return formatted;
};

function format(txt,compress/*是否为压缩模式*/){/* 格式化JSON源码(对象转换为JSON文本) */  
        var indentChar = '    ';   
        if(/^\s*$/.test(txt)){   
            alert('数据为空,无法格式化! ');   
            return;   
        }   
        try{var data=eval('('+txt+')');}   
        catch(e){   
            alert('数据源语法错误,格式化失败! 错误信息: '+e.description,'err');   
            return;   
        };   
        var draw=[],last=false,This=this,line=compress?'':'\n',nodeCount=0,maxDepth=0;   
           
        var notify=function(name,value,isLast,indent/*缩进*/,formObj){   
            nodeCount++;/*节点计数*/  
            for (var i=0,tab='';i<indent;i++ )tab+=indentChar;/* 缩进HTML */  
            tab=compress?'':tab;/*压缩模式忽略缩进*/  
            maxDepth=++indent;/*缩进递增并记录*/  
            if(value&&value.constructor==Array){/*处理数组*/  
                draw.push(tab+(formObj?('"'+name+'":'):'')+'['+line);/*缩进'[' 然后换行*/  
                for (var i=0;i<value.length;i++)   
                    notify(i,value[i],i==value.length-1,indent,false);   
                draw.push(tab+']'+(isLast?line:(','+line)));/*缩进']'换行,若非尾元素则添加逗号*/  
            }else   if(value&&typeof value=='object'){/*处理对象*/  
                    draw.push(tab+(formObj?('"'+name+'":'):'')+'{'+line);/*缩进'{' 然后换行*/  
                    var len=0,i=0;   
                    for(var key in value)len++;   
                    for(var key in value)notify(key,value[key],++i==len,indent,true);   
                    draw.push(tab+'}'+(isLast?line:(','+line)));/*缩进'}'换行,若非尾元素则添加逗号*/  
                }else{   
                        if(typeof value=='string')value='"'+value+'"';   
                        draw.push(tab+(formObj?('"'+name+'":'):'')+value+(isLast?'':',')+line);   
                };   
        };   
        var isLast=true,indent=0;   
        notify('',data,isLast,indent,false);   
        return draw.join('');   
    }