如何将JavaScript对象转换为字符串?

例子:

var o = {a:1, b:2}
console.log(o)
console.log('Item: ' + o)

输出:

对象{a=1, b=2} //非常好的可读输出:) Item: [object object] //不知道里面有什么:(


当前回答

Stringify-object是yeoman团队制作的一个很好的NPM库:https://www.npmjs.com/package/stringify-object

npm install stringify-object

然后:

const stringifyObject = require('stringify-object');
stringifyObject(myCircularObject);

显然,只有当循环对象使用JSON.stringify()会失败时,它才有趣;

其他回答

当然,要将对象转换为字符串,你必须使用自己的方法,例如:

function objToString (obj) {
    var str = '';
    for (var p in obj) {
        if (Object.prototype.hasOwnProperty.call(obj, p)) {
            str += p + '::' + obj[p] + '\n';
        }
    }
    return str;
}

实际上,以上只是展示了一般方法;您可能希望使用诸如http://phpjs.org/functions/var_export:578或http://phpjs.org/functions/var_dump:604之类的东西

或者,如果你不使用方法(函数作为对象的属性),你可以使用新的标准(但在旧的浏览器中没有实现,尽管你也可以找到一个实用工具来帮助它们),JSON.stringify()。但同样,如果对象使用的函数或其他属性不能序列化为JSON,这将不起作用。

更新:

一个更现代的解决方案是:

function objToString (obj) {
    let str = '';
    for (const [p, val] of Object.entries(obj)) {
        str += `${p}::${val}\n`;
    }
    return str;
}

or:

function objToString (obj) {
    return Object.entries(obj).reduce((str, [p, val]) => {
        return `${str}${p}::${val}\n`;
    }, '');
}
setobjToString:function(obj){
        var me =this;
        obj=obj[0];
        var tabjson=[];
        for (var p in obj) {
            if (obj.hasOwnProperty(p)) {
                if (obj[p] instanceof Array){
                    tabjson.push('"'+p +'"'+ ':' + me.setobjToString(obj[p]));
                }else{
                    tabjson.push('"'+p +'"'+':"'+obj[p]+'"');
                }
            }
        }  tabjson.push()
        return '{'+tabjson.join(',')+'}';
    }
var o = {a:1, b:2};

o.toString=function(){
  return 'a='+this.a+', b='+this.b;
};

console.log(o);
console.log('Item: ' + o);

因为Javascript v1.0可以在任何地方工作(甚至是IE) 这是一种本地方法,允许在调试和生产过程中对对象进行定制 https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Object/toString

有用的例子

var Ship=function(n,x,y){
  this.name = n;
  this.x = x;
  this.y = y;
};
Ship.prototype.toString=function(){
  return '"'+this.name+'" located at: x:'+this.x+' y:'+this.y;
};

alert([new Ship('Star Destroyer', 50.001, 53.201),
new Ship('Millennium Falcon', 123.987, 287.543),
new Ship('TIE fighter', 83.060, 102.523)].join('\n'));//now they can battle!
//"Star Destroyer" located at: x:50.001 y:53.201
//"Millennium Falcon" located at: x:123.987 y:287.543
//"TIE fighter" located at: x:83.06 y:102.523

还有,作为奖励

function ISO8601Date(){
  return this.getFullYear()+'-'+(this.getMonth()+1)+'-'+this.getDate();
}
var d=new Date();
d.toString=ISO8601Date;//demonstrates altering native object behaviour
alert(d);
//IE6   Fri Jul 29 04:21:26 UTC+1200 2016
//FF&GC Fri Jul 29 2016 04:21:26 GMT+1200 (New Zealand Standard Time)
//d.toString=ISO8601Date; 2016-7-29

Stringify-object是yeoman团队制作的一个很好的NPM库:https://www.npmjs.com/package/stringify-object

npm install stringify-object

然后:

const stringifyObject = require('stringify-object');
stringifyObject(myCircularObject);

显然,只有当循环对象使用JSON.stringify()会失败时,它才有趣;

/*
    This function is as JSON.Stringify (but if you has not in your js-engine you can use this)
    Params:
        obj - your object
        inc_ident - can be " " or "\t".
        show_types - show types of object or not
        ident - need for recoursion but you can not set this parameter.
*/
function getAsText(obj, inc_ident, show_types, ident) {
    var res = "";
    if (!ident)
        ident = "";
    if (typeof(obj) == "string") {
        res += "\"" + obj + "\" ";
        res += (show_types == true) ? "/* typeobj: " + typeof(obj) + "*/" : "";
    } else if (typeof(obj) == "number" || typeof(obj) == "boolean") {
        res += obj;
        res += (show_types == true) ? "/* typeobj: " + typeof(obj) + "*/" : "";
    } else if (obj instanceof Array) {
        res += "[ ";
        res += show_types ? "/* typeobj: " + typeof(obj) + "*/" : "";
        res += "\r\n";
        var new_ident = ident + inc_ident;
        var arr = [];
        for(var key in obj) {
            arr.push(new_ident + getAsText(obj[key], inc_ident, show_types, new_ident));
        } 
        res += arr.join(",\r\n") + "\r\n";
        res += ident + "]";
    } else {
        var new_ident = ident + inc_ident;      
        res += "{ ";
        res += (show_types == true) ? "/* typeobj: " + typeof(obj) + "*/" : "";
        res += "\r\n";
        var arr = [];
        for(var key in obj) {
            arr.push(new_ident + '"' + key + "\" : " + getAsText(obj[key], inc_ident, show_types, new_ident));
        }
        res += arr.join(",\r\n") + "\r\n";
        res += ident + "}\r\n";
    } 
    return res;
};

示例:

var obj = {
    str : "hello",
    arr : ["1", "2", "3", 4],
b : true,
    vobj : {
        str : "hello2"
    }
}

var ForReading = 1, ForWriting = 2;
var fso = new ActiveXObject("Scripting.FileSystemObject")
f1 = fso.OpenTextFile("your_object1.txt", ForWriting, true)
f1.Write(getAsText(obj, "\t"));
f1.Close();

f2 = fso.OpenTextFile("your_object2.txt", ForWriting, true)
f2.Write(getAsText(obj, "\t", true));
f2.Close();

your_object1.txt:

{ 
    "str" : "hello" ,
    "arr" : [ 
        "1" ,
        "2" ,
        "3" ,
        4
    ],
    "b" : true,
    "vobj" : { 
        "str" : "hello2" 
    }

}

your_object2.txt:

{ /* typeobj: object*/
    "str" : "hello" /* typeobj: string*/,
    "arr" : [ /* typeobj: object*/
        "1" /* typeobj: string*/,
        "2" /* typeobj: string*/,
        "3" /* typeobj: string*/,
        4/* typeobj: number*/
    ],
    "b" : true/* typeobj: boolean*/,
    "vobj" : { /* typeobj: object*/
        "str" : "hello2" /* typeobj: string*/
    }

}