原生js实现JSON.parse()和JSON.stringify()

function myJsonStringify(obj) {
        let type = typeof obj;
        if (type !== "object" || type === null) {
            if (/string|undefined|function/.test(type)) {
                obj = ‘"‘ + obj + ‘"‘;
            }
            return String(obj);
        } else {
            let json = [],
                arr = (obj && obj.constructor === Array);

            for (let k in obj) {
                let v = obj[k];
                let type = typeof v;

                if (/string|undefined|function/.test(type)) {
                    v = ‘"‘ + v + ‘"‘;
                } else if (type === "object") {
                    v = myJsonStringify(v);
                }

                json.push((arr ? "" : ‘"‘ + k + ‘":‘) + String(v));
            }
            return (arr ? "[" : "{") + String(json) + (arr ? "]" : "}")
        }
    }

(function(NS){
var simpleTypes=["number","boolean","undefined","string","function"]
function stringify(object){
    var type=typeof object
    if(indexOf(simpleTypes,type)>-1){
        return parseSimpleObject(object);
    }
    if(object instanceof Array){
        var len=object.length;
        var resArr=[];
        for(var i=0;i<len;i++){
            var itemType=typeof object[i];
            if(indexOf(simpleTypes,itemType)>-1){
                if(itemType!="undefined"){
                    resArr.push(parseSimpleObject(object[i]));
                }
                else{
                    resArr.push(‘null‘)
                }
            }
            else{
                resArr.push(stringify(object[i]))
            }
        }
        return "["+resArr.join(",")+ "]"
    }
    if(object instanceof Object){
        if(object==null){
            return "null"
        }
        var resArr=[]
        for(var name in object){
            var itemType=typeof object[name];
            if(indexOf(simpleTypes,itemType)>-1){
                if(itemType!=‘undefined‘){
                    resArr.push("\"" + name + "\":" + parseSimpleObject(object[name]))
                }
            }
            else{
                resArr.push("\"" + name +"\":" +stringify(object[name]))
            }
        }
        return "{" +resArr.join(",") +"}"
    }
}
function parseSimpleObject(object){
    var type=typeof object;
    if(type=="string"||type=="function"){
        return "\"" + object.toString().replace("\"","\\\"") + "\""
    }
    if(type=="number"||type=="boolean"){
        return object.toString()
    }
    if(type=="undefined"){
        return  "undefined"
    }
    return  "\"" +object.toString().replace("\"","\\\"") +"\""
}
function indexOf(arr,val){
    for(var i=0;i<arr.length;i++){
        if(arr[i]===val){
            return i;
        }
    }
    return -1
}
NS.stringify=function(object,isEncodeZh){
    var res=stringify(object)
    if(isEncodeZh){
        var encodeRes="";
        for(var i=0;i<res.length;i++){
            if(res.charCodeAt(i)<Oxff){
                encodeRes+=res[i]
            }
            else{
                encodeRes+="\\u"+res.charCodeAt(i).toString(16);
            }
        }
        res=encodeRes
    }
    return res;
}
})(window);

var json=‘{"a":"1","b":2}‘
 var obj=eval("("+json+")");

var func=new Function(arg1,arg2,...,functionBody)
var jsonStr=‘{"age":20,"name":"jack"}‘
var json=(new Function(‘return‘+jsonStr))()