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:(
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
也许你正在寻找
JSON.stringify(JSON.stringify(obj))
"{\"id\":30}"
其他回答
这里没有一个解决方案对我有效。JSON。stringify似乎是很多人所说的,但它削减了函数,并且在我测试时尝试的一些对象和数组似乎很坏。
我做了自己的解决方案,至少在Chrome中工作。把它贴在这里,这样任何在谷歌上看到的人都能找到它。
//Make an object a string that evaluates to an equivalent object
// Note that eval() seems tricky and sometimes you have to do
// something like eval("a = " + yourString), then use the value
// of a.
//
// Also this leaves extra commas after everything, but JavaScript
// ignores them.
function convertToText(obj) {
//create an array that will later be joined into a string.
var string = [];
//is object
// Both arrays and objects seem to return "object"
// when typeof(obj) is applied to them. So instead
// I am checking to see if they have the property
// join, which normal objects don't have but
// arrays do.
if (typeof(obj) == "object" && (obj.join == undefined)) {
string.push("{");
for (prop in obj) {
string.push(prop, ": ", convertToText(obj[prop]), ",");
};
string.push("}");
//is array
} else if (typeof(obj) == "object" && !(obj.join == undefined)) {
string.push("[")
for(prop in obj) {
string.push(convertToText(obj[prop]), ",");
}
string.push("]")
//is function
} else if (typeof(obj) == "function") {
string.push(obj.toString())
//all other values can be done with JSON.stringify
} else {
string.push(JSON.stringify(obj))
}
return string.join("")
}
编辑:我知道这段代码可以改进,但只是从来没有做过。用户andrey在评论中提出了一个改进:
这里有一点变化的代码,它可以处理'null'和'undefined',也没有添加过多的逗号。
使用它在你自己的风险,因为我没有验证它在所有。请随意提出任何额外的改进意见。
JSON方法远不如Gecko引擎的. tosource()原语。
有关比较测试,请参阅SO文章响应。
同样,上面的答案指的是http://forums.devshed.com/javascript-development-115/tosource-with-arrays-in-ie-386109.html,它像JSON一样(另一篇文章http://www.davidpirek.com/blog/object-to-string-how-to-deserialize-json通过“ExtJs JSON编码源代码”使用)不能处理循环引用,并且是不完整的。下面的代码显示了它的(欺骗的)限制(修正为处理无内容的数组和对象)。
(直接链接到//forums.devshed.com/中的代码…/ tosource - -数组在ie - 386109)
javascript:
Object.prototype.spoof=function(){
if (this instanceof String){
return '(new String("'+this.replace(/"/g, '\\"')+'"))';
}
var str=(this instanceof Array)
? '['
: (this instanceof Object)
? '{'
: '(';
for (var i in this){
if (this[i] != Object.prototype.spoof) {
if (this instanceof Array == false) {
str+=(i.match(/\W/))
? '"'+i.replace('"', '\\"')+'":'
: i+':';
}
if (typeof this[i] == 'string'){
str+='"'+this[i].replace('"', '\\"');
}
else if (this[i] instanceof Date){
str+='new Date("'+this[i].toGMTString()+'")';
}
else if (this[i] instanceof Array || this[i] instanceof Object){
str+=this[i].spoof();
}
else {
str+=this[i];
}
str+=', ';
}
};
str=/* fix */(str.length>2?str.substring(0, str.length-2):str)/* -ed */+(
(this instanceof Array)
? ']'
: (this instanceof Object)
? '}'
: ')'
);
return str;
};
for(i in objRA=[
[ 'Simple Raw Object source code:',
'[new Array, new Object, new Boolean, new Number, ' +
'new String, new RegExp, new Function, new Date]' ] ,
[ 'Literal Instances source code:',
'[ [], {}, true, 1, "", /./, function(){}, new Date() ]' ] ,
[ 'some predefined entities:',
'[JSON, Math, null, Infinity, NaN, ' +
'void(0), Function, Array, Object, undefined]' ]
])
alert([
'\n\n\ntesting:',objRA[i][0],objRA[i][1],
'\n.toSource()',(obj=eval(objRA[i][1])).toSource(),
'\ntoSource() spoof:',obj.spoof()
].join('\n'));
显示:
testing:
Simple Raw Object source code:
[new Array, new Object, new Boolean, new Number, new String,
new RegExp, new Function, new Date]
.toSource()
[[], {}, (new Boolean(false)), (new Number(0)), (new String("")),
/(?:)/, (function anonymous() {}), (new Date(1303248037722))]
toSource() spoof:
[[], {}, {}, {}, (new String("")),
{}, {}, new Date("Tue, 19 Apr 2011 21:20:37 GMT")]
and
testing:
Literal Instances source code:
[ [], {}, true, 1, "", /./, function(){}, new Date() ]
.toSource()
[[], {}, true, 1, "", /./, (function () {}), (new Date(1303248055778))]
toSource() spoof:
[[], {}, true, 1, ", {}, {}, new Date("Tue, 19 Apr 2011 21:20:55 GMT")]
and
testing:
some predefined entities:
[JSON, Math, null, Infinity, NaN, void(0), Function, Array, Object, undefined]
.toSource()
[JSON, Math, null, Infinity, NaN, (void 0),
function Function() {[native code]}, function Array() {[native code]},
function Object() {[native code]}, (void 0)]
toSource() spoof:
[{}, {}, null, Infinity, NaN, undefined, {}, {}, {}, undefined]
JSON似乎接受了第二个参数,可以帮助函数- replace,这以最优雅的方式解决了转换问题:
JSON.stringify(object, (key, val) => {
if (typeof val === 'function') {
return String(val);
}
return val;
});
循环引用
通过使用下面的替换器,我们可以产生更少冗余的JSON -如果源对象包含对某个对象的多次引用,或者包含循环引用-那么我们通过特殊的路径字符串(类似于JSONPath)引用它-我们如下所示
let s = JSON.stringify(obj, refReplacer());
function refReplacer() { let m = new Map(), v= new Map(), init = null; return function(field, value) { let p= m.get(this) + (Array.isArray(this) ? `[${field}]` : '.' + field); let isComplex= value===Object(value) if (isComplex) m.set(value, p); let pp = v.get(value)||''; let path = p.replace(/undefined\.\.?/,''); let val = pp ? `#REF:${pp[0]=='[' ? '$':'$.'}${pp}` : value; !init ? (init=value) : (val===init ? val="#REF:$" : 0); if(!pp && isComplex) v.set(value, path); return val; } } // --------------- // TEST // --------------- // gen obj with duplicate references let a = { a1: 1, a2: 2 }; let b = { b1: 3, b2: "4" }; let obj = { o1: { o2: a }, b, a }; // duplicate reference a.a3 = [1,2,b]; // circular reference b.b3 = a; // circular reference let s = JSON.stringify(obj, refReplacer(), 4); console.log(s);
奖励:这里是这种序列化的逆函数
function parseRefJSON(json) { let objToPath = new Map(); let pathToObj = new Map(); let o = JSON.parse(json); let traverse = (parent, field) => { let obj = parent; let path = '#REF:$'; if (field !== undefined) { obj = parent[field]; path = objToPath.get(parent) + (Array.isArray(parent) ? `[${field}]` : `${field?'.'+field:''}`); } objToPath.set(obj, path); pathToObj.set(path, obj); let ref = pathToObj.get(obj); if (ref) parent[field] = ref; for (let f in obj) if (obj === Object(obj)) traverse(obj, f); } traverse(o); return o; } // ------------ // TEST // ------------ let s = `{ "o1": { "o2": { "a1": 1, "a2": 2, "a3": [ 1, 2, { "b1": 3, "b2": "4", "b3": "#REF:$.o1.o2" } ] } }, "b": "#REF:$.o1.o2.a3[2]", "a": "#REF:$.o1.o2" }`; console.log('Open Chrome console to see nested fields:'); let obj = parseRefJSON(s); console.log(obj);
如果您正在使用Dojo javascript框架,那么已经有一个内置函数来完成此工作:Dojo . tojson(),它将像这样使用。
var obj = {
name: 'myObj'
};
dojo.toJson(obj);
它将返回一个字符串。如果要将对象转换为json数据,则添加第二个参数true。
dojo.toJson(obj, true);
http://dojotoolkit.org/reference-guide/dojo/toJson.html#dojo-tojson